Intelligent solid state lighting

ABSTRACT

A light fixture, using one or more solid state light emitting elements utilizes a diffusely reflect chamber to provide a virtual source of uniform output light, at an aperture or at a downstream optical processing element of the system. Systems disclosed herein also include a detector, which detects electromagnetic energy from the area intended to be illuminated by the system, of a wavelength absent from a spectrum of the combined light system output. A system controller is responsive to the signal from the detector. The controller typically may control one or more aspects of operation of the solid state light emitter(s), such as system ON-OFF state or system output intensity or color. Examples are also discussed that use the detection signal for other purposes, e.g. to capture data that may be carried on electromagnetic energy of the wavelength sensed by the detector.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/294,564 filed on Dec. 6, 2005, which is a continuation ofU.S. patent application Ser. No. 10/832,464, filed Apr. 27, 2004 nowU.S. Pat. No. 6,995,355, which is a continuation-in-part of U.S. patentapplication Ser. No. 10/601,101, filed Jun. 23, 2003, the disclosures ofwhich are entirely incorporated herein by reference; and thisapplication claims the benefits of the filing dates of those earlierapplications.

TECHNICAL FIELD

The present subject matter relates to techniques and equipment toprovide visible lighting, particularly highly uniform visible lightemissions and/or light emissions of a desired visible spectralcharacteristic, using solid state light emitting elements, incombination with sensing of energy of a wavelength that is absent fromthe light emitted for purposes of the visible illumination so as tofacilitate intelligent applications such as occupancy detection, remotecontrol, data communications or the like.

BACKGROUND

An increasing variety of lighting applications require a preciselycontrolled spectral characteristic of the radiant electromagneticenergy. It has long been known that combining the light of one colorwith the light of another color creates a third color. For example, thecommonly used primary colors Red, Green and Blue of different amountscan be combined to produce almost any color in the visible spectrum.Adjustment of the amount of each primary color enables adjustment of thespectral properties of the combined light stream. Recent developmentsfor selectable color systems have utilized solid state devices, such aslight emitting diodes, as the sources of the different light colors.

Light emitting diodes (LEDs) were originally developed to providevisible indicators and information displays. For such luminanceapplications, the LEDs emitted relatively low power. However, in recentyears, improved LEDs have become available that produce relatively highintensities of output light. These higher power LEDs, for example, havebeen used in arrays for traffic lights. Today, LEDs are available inalmost any color in the color spectrum.

Systems are known which combine controlled amounts of projected lightfrom at least two LEDs of different primary colors. Attention isdirected, for example, to U.S. Pat. Nos. 6,459,919, 6,166,496 and6,150,774. Typically, such systems have relied on using pulse-widthmodulation or other modulation of the LED driver signals to adjust theintensity of each LED color output. Such prior systems have relied ondirect radiation or illumination from the individual source LEDs.

In some applications, the LEDs may represent undesirably bright sourcesif viewed directly. Solid state light emitting elements have smallemission output areas and typically they appear as small point sourcesof light. As the output power of solid state light emitting elementsincreases, the intensity provided over such a small output arearepresents a potentially hazardous light source. Increasingly, directobservation of such sources, particularly for any substantial period oftime, may cause eye injury.

Also, the direct illumination from LEDs providing multiple colors oflight has not provided optimum combination throughout the field ofillumination. Pixelation often is a problem with prior solid statelighting devices. In some systems, the observer can see the separatered, green and blue lights from the LEDs at short distances from thefixture, even if the LEDs are covered by a translucent diffuser. Thelight output from individual LEDs or the like appear asidentifiable/individual point sources or ‘pixels.’ Integration of colorsby the eye becomes effective only at longer distances, otherwise thefixture output exhibits striations of different colors.

Another problem arises from long-term use of LED type light sources. Asthe LEDs age, the output intensity for a given input level of the LEDdrive current decreases. As a result, it may be necessary to increasepower to an LED to maintain a desired output level. This increases powerconsumption. In some cases, the circuitry may not be able to provideenough light to maintain the desired light output level. As performanceof the LEDs of different colors declines differently with age (e.g. dueto differences in usage), it may be difficult to maintain desiredrelative output levels and therefore difficult to maintain the desiredspectral characteristics of the combined output. The output levels ofLEDs also vary with actual temperature (thermal) that may be caused bydifference in ambient conditions or different operational heating and/orcooling of different LEDs. Temperature induced changes in performancecause changes in the spectrum of light output.

U.S. Pat. No. 5,803,592 suggests a light source design intended toproduce a high uniformity substantially Lambertian output. The disclosedlight design used a diffusely reflective hemispherical first reflectorand a diffuser. The light did not use a solid state type light emittingelement. The light source was an arc lamp, metal halide lamp or filamentlamp. The light included a second reflector in close proximity to thelamp (well within the volume enclosed by the hemispherical firstreflector and the diffuser) to block direct illumination of and throughthe diffuser by the light emitting element, that is to say, so as toreduce the apparent surface brightness of the center of the light outputthat would otherwise result from direct output from the source.

U.S. Pat. No. 6,007,225 to Ramer et al. (Assigned to Advanced OpticalTechnologies, L.L.C.) discloses a directed lighting system utilizing aconical light deflector. At least a portion of the interior surface ofthe conical deflector has a specular reflectivity. In several disclosedembodiments, the source is coupled to an optical integrating cavity; andan outlet aperture is coupled to the narrow end of the conical lightdeflector. This patented lighting system provides relatively uniformlight intensity and efficient distribution of light over a field ofillumination defined by the angle and distal edge of the deflector.However, this patent does not discuss particular color combinations oreffects or address specific issues related to lighting using one or moresolid state light emitting elements.

Hence, a need still exists for a technique to efficiently processelectromagnetic energy from one or more solid state light emittingsources and direct uniform electromagnetic energy effectively toward adesired field of illumination, in a manner that addresses as many of theabove discussed issues as practical.

Also, there are a variety of consumer needs and applications thatrequire additional intelligence in association with lighting equipment.It is often desirable to provide enhanced control features for the lightand/or for associated equipment, either in the form of wireless remotecontrol or in response to occupancy detection.

A variety of technologies are known, for example based on ultrasonicsensing and passive or active sensing, to determine occupancy of an areato be illuminated and control one or more light fixtures in response tothe occupancy determination. Typically, the occupancy sensor is mountedin a wall or ceiling of the area that the lighting device is intended toilluminate. Such control based on sensing of occupancy reduces energyand maintenance costs by turning-off the light(s) when not needed.Typically, existing occupancy sensors have been used with conventionallighting devices, such as fluorescent and incandescent lamps. Generalstrategies of occupancy responsive control may be applicable to LEDbased lighting, but systems and methodologies have not yet beendeveloped that specifically integrate such control strategies into LEDbased lighting in a highly effective and efficient manner.

Hence, it would also be desirable that solid state lighting solutionsalso support enhanced sensing and processing capabilities forcommunication purposes, automation and control of the lighting equipmentand/or other systems, monitoring, or the like.

SUMMARY

A lighting system as disclosed herein includes a chamber having areflective interior surface. At least a portion of the interior surfacehas a diffuse reflectivity, such that the chamber combines light bydiffuse reflection within the chamber. Typically, examples implement thechamber as an optical integrating cavity. The chamber has an opticalaperture through which combined light emerges in a direction forlighting an area intended to be illuminated by the system. One or moresolid state light emitting elements supply light to the chamber. Eachsolid state light emitting element is coupled so as to supply light tothe chamber in such a manner that substantially all light emitted fromeach solid state light emitting element reflects diffusely at least oncewithin the interior of the chamber before combined light emissionthrough the optical aperture toward the area intended to be illuminatedby the system. The systems disclosed herein also include a detector,which detects electromagnetic energy from the area intended to beilluminated by the system, of a wavelength absent from a spectrum of thecombined light system output for illumination purposes.

A system controller will receive the signal from the detector. Inseveral examples, the controller controls one or more aspects ofoperation of the solid state light emitter(s). The controller mayperform such a function of light control in response to the detectorsignal, for example by turning the solid state light emitter(s) on oroff or otherwise controlling the amount of light energy output by eachof the solid state light emitter(s). The detector signal may represent aremote control command, or the controller may process the signal todetect occupancy status of the illuminated area. However, examples arealso discussed that use the detection signal for other purposes, forexample, to capture data that may be carried on electromagnetic energyof the particular wavelength sensed by the detector.

Additional objects, advantages and novel features of the examples willbe set forth in part in the description which follows, and in part willbecome apparent to those skilled in the art upon examination of thefollowing and the accompanying drawings or may be learned by productionor operation of the examples. The objects and advantages of the presentsubject matter may be realized and attained by means of themethodologies, instrumentalities and combinations particularly pointedout in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations in accord withthe present concepts, by way of example only, not by way of limitations.In the figures, like reference numerals refer to the same or similarelements.

FIG. 1A illustrates an example of an intelligent light emitting systemincluding a fixture using a solid state light emitting element, withcertain elements of the fixture shown in cross-section.

FIG. 1B illustrates another example of an intelligent light emittingsystem using a plurality of solid state light emitting elements and afeedback sensor, with certain elements of the fixture shown incross-section.

FIG. 1C illustrates another example of an intelligent light emittingsystem using white light type solid state light emitting elements ofdifferent color temperatures, with certain elements of the fixture shownin cross-section.

FIG. 1D illustrates another example of an intelligent light emittingsystem, using white type solid state light emitting elements ofsubstantially the same color temperature, with certain elements of thefixture shown in cross-section.

FIG. 1E illustrates an example of an intelligent light emitting systemin which one of the solid state light emitting elements emitsultraviolet (UV) light.

FIG. 1F illustrates an example of an intelligent light emitting systemin which one of the solid state light emitting elements emits infrared(IR) light.

FIG. 2 illustrates an example of an intelligent radiant energy emittingsystem using primary color LEDs as solid state light emitting elements,with certain fixture elements shown in cross-section.

FIG. 3 is a functional block diagram of the electrical components, ofone of the intelligent systems, using programmable digital controllogic.

FIG. 4 is a flow chart illustrating use of an intelligent solid statelighting system, with the sensing and processing configured foroccupancy detection and attendant control of the operation of thelighting system.

FIGS. 5A and 5B are simplified signal diagrams illustrating IR lightlevels and associated thresholds, useful in understanding an example ofoperation in accord with the process flow of FIG. 4.

FIG. 6 is a diagram, illustrating a number of radiant energy emittingsystems with common control from a master control unit.

FIG. 7 illustrates another example of an intelligent light emittingsystem, using fiber optic links from the LEDs to the optical integratingcavity.

FIG. 8 illustrates another example of an intelligent light emittingsystem, with certain elements thereof shown in cross-section.

FIG. 9 is a bottom view of the fixture in the system of FIG. 8.

FIGS. 10A to 10C are cross-sectional views of additional examples, ofoptical cavity LED light fixtures, with several alternative elements forprocessing of the combined light emerging from the cavity.

FIG. 11 illustrates another example of an intelligent light emittingsystem, utilizing principles of mask and cavity type constructiveocclusion.

FIG. 12 is a bottom view of the fixture in the system of FIG. 10.

FIG. 13 illustrates an alternate example of an intelligent lightemitting system, utilizing principles of constructive occlusion.

FIG. 14 is a top plan view of the fixture in the system of FIG. 12 andassociated detectors.

FIG. 15A is a cross-sectional view of another example of a lightfixture, utilizing principles of mask-and-cavity constructive occlusion.

FIG. 15B is a cross-section of the fixture of FIG. 15A taken along lineB-B.

FIG. 16A a top plan view of another example of a fixture, utilizingprinciples of mask-and-cavity constructive occlusion, having nestedoptical integrating cavities for emission and detection.

FIG. 16B is a cross-sectional view of the fixture of FIG. 16A, takenalong line B-B.

FIG. 16C is a cross-sectional view of the fixture, taken along line C-Cof FIG. 16B.

FIG. 16D is a cross-sectional view of the fixture, taken along line D-Dof FIG. 16B.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. However, it should be apparent to those skilledin the art that the present teachings may be practiced without suchdetails. In other instances, well known methods, procedures, components,and circuitry have been described at a relatively high-level, withoutdetail, in order to avoid unnecessarily obscuring aspects of the presentconcepts. Reference now is made in detail to the examples illustrated inthe accompanying drawings and discussed below.

A lighting system as disclosed herein includes a chamber having areflective interior surface. At least a portion of the interior surfacehas a diffuse reflectivity, such that the chamber combines light bydiffuse reflection within the chamber. Typical examples implement thechamber as an optical integrating cavity. The chamber has an opticalaperture through which combined light emerges in a direction forlighting an area intended to be illuminated by the system. One or moresolid state light emitting elements supply light to the chamber. Eachsolid state light emitting element is coupled so as to supply light tothe chamber in such a manner that substantially all light emitted fromeach solid state light emitting element reflects diffusely at least oncewithin the interior of the chamber before combined light emissionthrough the optical aperture toward the area intended to be illuminatedby the system. Additional optical processing elements may process thecombined light from the aperture.

The optical processing by the chamber and other elements, in many of theexamples disclosed herein, converts one or more solid state lightsources of relatively small areas (“point sources”) into a virtualsource of a larger area. The light output forms a virtual source outputin that the fixture or system output, e.g., at the optical aperture ofthe chamber or an output of a further optical processing element, formsthe apparent source of light as perceived from the area that is beingilluminated. Point source light generated by one or more solid statelight emitters, is not individually perceived as the source(s) of lightfrom the perspective of the illuminated area. Instead, the virtualsource appears as the single source of uniform light output over alarger output area.

The systems disclosed herein also include a detector, for example as anintegral element of a light fixture. The detector detectselectromagnetic energy from the area intended to be illuminated by thesystem, of a wavelength not present in (absent from) a spectrum of thecombined light system output, that is to say generated by the solidstate light emitter(s) and the chamber for the system's intendedillumination application. The system may be passive, in that thedetector detects light from within the area without itself supplyingelectromagnetic energy of the particular wavelength into the area.Alternatively, the system may be active, in that the system generateselectromagnetic energy of the particular wavelength and the detectordetects reflections of that electromagnetic energy from the illuminatedarea. The detector and source may process to different wavelengths, e.g.for two-way communication. The detector may be coupled to the chamber ora second chamber, or the detector may be outside the chamber. The sourcemay supply light through the chamber or it may be separate.

A system controller will receive the signal from the detector. Thecontroller in some examples controls one or more aspects of operation ofthe solid state light emitter(s). The controller may control lighting inresponse to the detector signal, for example by turning the solid statelight emitter(s) on or off or otherwise controlling the amount of lightenergy output by each of the solid state light emitter(s). However,examples are also discussed that use the detection signal for otherpurposes, for example, to capture data that may be carried onelectromagnetic energy of the particular wavelength sensed by thedetector.

With that overview, it may be helpful now to consider examples withspecific reference to the drawings.

As shown in FIG. 1A, an exemplary lighting system 1A includes an opticalintegrating cavity 2 having a reflective interior surface. At least aportion of the interior surface of the cavity 2 exhibits a diffusereflectivity. The cavity 2 may have various shapes. The illustratedcross-section would be substantially the same if the cavity ishemispherical or if the cavity is semi-cylindrical with a lateralcross-section taken perpendicular to the longitudinal axis. It isdesirable that the cavity surface have a highly efficient reflectivecharacteristic, e.g. a reflectivity equal to or greater than 90%, withrespect to the relevant wavelengths. The entire interior surface may bediffusely reflective, or one or more substantial portions may bediffusely reflective while other portion(s) of the cavity surface mayhave different light responsive characteristics. In some examples, oneor more other portions are substantially specular.

For purposes of the discussion, the cavity 2 in the system 1A is assumedto be hemispherical. In such an example, the optical cavity 2 comprisesa hemispherical dome 3 and a substantially flat cover plate 4, with thereflective cavity formed between reflective surfaces of the dome 3 andplate 4. At least the interior facing surface(s) of the dome 3 andpossibly interior facing surface of the cover plate 4 are highlydiffusely reflective, so that the resulting cavity 2 is highly diffuselyreflective with respect to the radiant energy spectrum produced byand/or detected by the system 1A. As a result, the cavity 2 is anintegrating type optical cavity. Although shown as separate elements,the dome and plate may be formed as an integral unit. The cavity 2 hasan optical aperture 5, which allows emission of reflected and diffusedlight C from within the interior of the cavity 2 into a region tofacilitate a humanly perceptible lighting application for the system 1A.

The lighting system 1A also includes at least one source of radiantelectromagnetic energy for illumination purposes. The fixture geometrydiscussed herein may be used with any appropriate type of sources ofradiant electromagnetic energy. Although other types of sources ofradiant electromagnetic energy may be used, such as various conventionalforms of incandescent, arc, neon and fluorescent lamp, at least onesource takes the form of a solid state light emitting element (S),represented by the single solid state lighting element (S) 6 in thedrawing. In a single source example, the element (S) 6 typically emitsvisible light for illumination application. In multi-source examplesdiscussed later, some source(s) may emit visible light and one or moreother sources may emit light in another part of the electromagneticspectrum. Each solid state light emitting element (S) 6 is coupled tosupply light to enter the cavity 2 at a point not directly observablethrough the aperture 5 from the region illuminated by the fixture outputC. Various couplings and various light entry locations may be used.

As discussed herein, applicable solid state light emitting elements (S)essentially include any of a wide range light emitting or generatingdevices formed from organic or inorganic semiconductor materials.Examples of solid state light emitting elements include semiconductorlaser devices and the like. Many common examples of solid state lightingelements, however, are classified as types of “light emitting diodes” or“LEDs.” This exemplary class of solid state light emitting devicesencompasses any and all types of semiconductor diode devices that arecapable of receiving an electrical signal and producing a responsiveoutput of electromagnetic energy. Thus, the term “LED” should beunderstood to include light emitting diodes of all types, light emittingpolymers, organic diodes, and the like. LEDs may be individuallypackaged, as in the illustrated examples. Of course, LED based devicesmay be used that include a plurality of LEDs within one package, forexample, multi-die LEDs that contain separately controllable red (R),green (G) and blue (B) LEDs within one package. Those skilled in the artwill recognize that “LED” terminology does not restrict the source toany particular type of package for the LED type source. Such termsencompass LED devices that may be packaged or non-packaged, chip onboard LEDs, surface mount LEDs, and any other configuration of thesemiconductor diode device that emits light. Solid state lightingelements may include one or more phosphors and/or nanophosphors basedupon quantum dots, which are integrated into elements of the package orlight processing elements of the fixture to convert at least someradiant energy to a different more desirable wavelength or range ofwavelengths.

The color or spectral characteristic of light or other electromagneticradiant energy relates to the frequency and wavelength of the energyand/or to combinations of frequencies/wavelengths contained within theenergy. Many of the examples relate to colors of light within thevisible portion of the spectrum, although examples also are discussedthat utilize or emit other energy. Electromagnetic energy, typically inthe form of light energy from the one or more solid state light sources(S) 6, is diffusely reflected and combined within the cavity 2 to formcombined light C for emission via the aperture 5. Such integration, forexample, may combine light from multiple sources. The integration tendsto form a relatively Lambertian distribution across the aperture. Whenviewed from the area illuminated by the combined light C, the apertureappears to have substantially infinite depth of the integrated light C.Also, the visible intensity is spread uniformly across the aperture, asopposed to individual small point sources of higher intensity as wouldbe seen if the one or more elements (S) 6 were directly visible withoutdiffuse reflection before emission through the aperture 5. Hence, thelight output C appears to emanate from a virtual source, at the aperture5 in this example.

Pixelation is a problem with many prior solid state lighting devices.When the fixture output is observed, the light output from individualLEDs or the like appear as identifiable/individual point sources or‘pixels.’ Even with diffusers or other forms of common mixing, thepixels of the sources are apparent. The observable output of such aprior system exhibits a high maximum-to-minimum intensity ratio. Insystems using multiple light color sources, e.g. RGB LEDs, unlessobserved from a substantial distance from the fixture, the light fromthe fixture often exhibits striations of different colors.

Systems and light fixtures as disclosed herein, however, do not exhibitsuch pixilation. Instead, the cavity output C appears as unpixelatedvirtual source of relatively uniform intensity distribution across theapparent output area of the fixture, e.g. across the optical aperture 5of the cavity 2. The optical integration sufficiently mixes the lightfrom the solid state light emitting elements 6 that the combined lightoutput C of the virtual source is at least substantially Lambertian indistribution across the optical output area of the fixture, that is tosay across the aperture 5 of the cavity 2. As a result, the combinedlight output C exhibits a relatively low maximum-to-minimum intensityratio across the aperture 5. In the examples shown herein, the combinedlight output exhibits a maximum to minimum ratio of 2 to 1 or less oversubstantially the entire optical output area. The examples rely onvarious implementations of the optical integrating cavity 2 as themixing element to achieve this level of output uniformity, however,other mixing elements could be used if they are configured to producesuch uniform output (Lambertian and/or relatively low maximum-to-minimumintensity ratio across the fixture's optical output area).

It also should be appreciated that solid state light emitting elements 6may be configured to generate electromagnetic radiant energy havingvarious bandwidths for a given spectrum (e.g. narrow bandwidth of aparticular color, or broad bandwidth centered about a particular), andmay use different configurations to achieve a given spectralcharacteristic. For example, one implementation of a white LED mayutilize a number of dies that generate different primary colors whichcombine to form essentially white light. In another implementation, awhite LED may utilize a semiconductor that generates light of arelatively narrow first spectrum in response to an electrical inputsignal, but the narrow first spectrum acts as a pump. The light from thesemiconductor “pumps” a phosphor material contained in the LED package,which in turn radiates a different typically broader spectrum of lightthat appears relatively white to the human observer.

The system 1A also includes a controller, shown in the example as acontrol circuit 7, which is responsive to a user actuation forcontrolling an amount of radiant electromagnetic energy supplied to thecavity 2 by the solid state light emitting element or elements 6 of thesystem 1A. The control circuit 7 typically includes a power supplycircuit coupled to a power source, shown as an AC power source 8. Thecontrol circuit 7 also includes one or more adjustable driver circuitsfor controlling the power applied to the solid state light emittingelements (S) 6 and thus the amount of radiant energy supplied to thecavity 2 by each source 6. The control circuit 7 may be responsive to anumber of different control input signals, for example, to one or moreuser inputs as shown by the arrow in FIG. 1A and possibly signals fromone or more feedback sensors, as discussed in more detail later.

The virtual source output light C has a spectral characteristic,typically in the visible light region of the spectrum. The system 1Aalso includes a detector 9. In this first example, the detector 9 sensesa characteristic of electromagnetic energy reflected within the cavity5. For purposes of the present discussion, the detector 9 is a device ofa type for sensing at least one wavelength of light not present in thespectrum of light output C from the aperture 5 that forms the virtualsource in this example. The wavelength may be a visible wavelengthcorresponding to a notch in the visible spectrum of output light C. Inother examples where the output C is entirely in the visible lightportion of the spectrum, the wavelength sensed by detector 9 is awavelength outside the visible spectrum, for example in the near or farinfrared (IR) range or in the ultraviolet (UV) range. Since the detector9 senses a wavelength not present in the spectrum of light output C andthus absent from the light generated by the solid state source 6, thedetector 9 is responsive to energy of that wavelength that enters thecavity 2 via the aperture 5 and reflects off the surface(s) of thecavity.

The detector 9 supplies a detection signal to the controller 7. Thecontroller 7 may control one or more operations of the system 1A inresponse to the detection signal, for example to turn the light output CON and OFF or to vary the intensity of the output (while ON).Alternatively, the controller 7 may process the signal for otherpurposes, e.g. to demodulate the signal to capture data that may becarried on the energy of the particular wavelength.

Examples are discussed below in which the detector 9 is outside and/orseparate from the cavity 2. However, in the first exemplary system 1,the detector 9 is coupled to a location in the optical integratingcavity 2 at which at least a substantial portion of the electromagneticenergy of the particular wavelength that enters the cavity 2 through theoptical aperture 5 is reflected one or more times off the reflectiveinterior surface of the cavity 2 before reaching the location ofcoupling to the detector 9. The detector 9 may be at or otherwisecoupled to any such point on a surface of the cavity 2, typically apoint not directly visible or illuminated through the aperture 5. In theexample, the detector 9 is mounted to receive light at a point on theplate 4.

Much as the aperture forms a virtual output source, it also forms avirtual detector surface. The optical processing of light before sensingby the detector makes the system uniformly sensitive at points on theaperture. The aperture is a substantially Lambertian detecting surface.

In this first example, the system 1A uses an active sensing approach, inthat the system 1A also includes a source 10 of electromagnetic energyof the wavelength sensed by detector 9. The source 10 may be anothersolid state light emitter similar to the source 6, but configured toemit a wavelength not present in the output light C. It is alsoenvisaged that the source 10 may be any other conventional source ofelectromagnetic energy (such as an incandescent lamp, a fluorescentlamp, an arc lamp, a halogen lamp, etc.) as long as the particularsource 10 provides electromagnetic energy of the appropriate wavelength.

Examples are discussed later in which the detector is outside thecavity, and the source 10 is coupled to supply light into the interiorof the optical integrating cavity, in a manner similar to the solidstate light source (S) 6. However, in this first example, the source 10is located for emission of electromagnetic energy of the particularwavelength from outside the optical integrating cavity 2 into at least aportion of the area intended to be illuminated by the virtual sourcelight output C, that is to say without passage of the energy from thesource 10 through the optical aperture 5. The source 10 may be mountedclose to the cavity 2 and may be an integral part of a fixture thatincludes the cavity, the solid state light source (S) 6 and the detector9. Alternatively, the source 10 may located at any other convenientposition from which it may illuminate at least a portion of the areathat the system 1A is intended to illuminate with the light output C.

The electromagnetic energy from the source 10 reflects back from one ormore objects in the area illuminated by the system 1A. At least aportion of the reflected energy enters the optical integrating cavity 2via the aperture 5. Such electromagnetic energy reflects one or moretimes off of the surfaces of the dome 3 and plate 4 that form the cavity2. One or more such reflections will diffuse the reflectedelectromagnetic energy. At least a portion of the electromagnetic energyof the particular wavelength, that is diffusely reflected within thecavity 2, is coupled to and sensed by detector 9. In response, thedetector 9 generates a signal that relates to the measured or sensedamount of that electromagnetic energy.

FIG. 1B shows another example of an intelligent lighting system, that isto say system 1B. The system 1B, for example, includes an opticalintegrating cavity 2 similar to that discussed above relative to FIG.1A. Again, the cavity 2 formed in the example by the dome 3 and thecover plate 4 has a reflective interior. At least one surface of theinterior of the cavity 2 is diffusely reflective, so that the cavitydiffusely reflects light and thereby integrates or combines light. Thecavity 2 has an optical aperture for allowing emission of reflectedlight from within the interior of the cavity as combined light Cdirected into a region to facilitate a humanly perceptible lightingapplication for the system 1B. The integration in the cavity 2effectively produces a virtual source of the output light C, in thiscase, again at the aperture 5.

In this type of exemplary system 1B, there are a number of solid statelight emitting elements (S) 6 for emitting light, similar to theelement(s) 6 used in the system 1A of FIG. 1A. At least one of the solidstate light emitting elements 6 emits visible light energy. The otheremitting element 6 typically emits visible light energy, although insome case the other element may produce other spectrums, e.g. in theultraviolet (UV) or infrared (IR) portions of the electromagneticspectrum. Each of the solid state light emitting elements (S) 6 supplieslight (visible, UV or IR) into the cavity 2 at a point not directlyobservable through the aperture from the region. Light from each source6 diffusely reflects at least once inside the cavity 2 before emissionas part of the combined light C that emerges through the aperture 2. Thesystem 1B could include a source of the additional wavelength, similarto the source 10 in the system 1A of FIG. 1A. However, in this example,the system does not include such an additional source. The system 1B mayalso include a user interface device for providing the means for userinput.

As in the earlier example, the virtual source output light C has aspectral characteristic, typically in the visible light region of thespectrum. The system 1B also includes a detector 9, for sensing acharacteristic of electromagnetic energy reflected within the cavity 5;and the detector 9 is a device of a type for sensing at least onewavelength of light not present in the spectrum of light generated foroutput C from the aperture 5 that forms the virtual source in thisexample. The wavelength may be a visible wavelength corresponding to anotch in the visible spectrum of output light C. In other examples wherethe output C is entirely in the visible light portion of the spectrum,the wavelength sensed by detector 9 is a wavelength outside the visiblespectrum, for example in the near or far infrared (IR) range or in theultraviolet (UV) range. Since the detector 9 senses a wavelength notpresent in the spectrum of light output C and thus absent from the lightgenerated by the solid state source 6, the detector 9 is responsive toenergy of that wavelength that enters the cavity 2 via the aperture 5and reflects off the surface(s) of the cavity.

The system 1B uses a passive sensing approach, in that the system 1Brelies on sensing of electromagnetic energy of the particular wavelengthemitted or reflected from other sources within the illuminated area,without the system 1B itself supplying energy of that wavelength. Forexample, the sensor 9 may passively detect IR from one or more heatsources within a room illuminated by the system 1B, such as one or morepersons who enter the room. The detector 9 is coupled to a location inthe optical integrating cavity 2 at which at least a substantial portionof the electromagnetic energy of the particular wavelength that entersthe cavity 2 through the optical aperture 5 is reflected one or moretimes off the reflective interior surface of the cavity 2 beforereaching the location of coupling to the detector 9. One or more of thereflections will diffuse the reflected electromagnetic energy. Thedetector 9 may be located at or otherwise coupled to any such point on asurface of the cavity 2, typically a point not directly visible orilluminated through the aperture 5. In the example, the detector 9 ismounted to receive light at a point on the plate 4.

Hence, at least a portion of the electromagnetic energy of theparticular wavelength, that is diffusely reflected within the cavity 2,is coupled to and sensed by detector 9. In response, the detector 9generates a signal that relates to the measured or sensed amount of thatelectromagnetic energy. As in the earlier example, the detector 9supplies the detection signal to the controller 7; and the controller 7may control one or more operations of the system 1B in response to thedetection signal. Alternatively, the controller 7 may process the signalfor other purposes, e.g. to demodulate the signal to capture data thatmay be carried on the energy of the particular wavelength. For two-waycommunication, the controller might modulate the drive of the emitters 6with downlink data, and the light sensed by the detector 9 would carrythe uplink data.

Some systems that use multiple solid state light emitting elements (S) 6may use sources 6 of the same type, that is to say a set of solid statelight emitting sources of a type intended to all produce electromagneticenergy of substantially the same spectral characteristic (assuming thesame or similar supply of power). All of the sources may be identicalwhite light (W) emitting elements or may all emit light of the sameprimary color. The system 1C (FIG. 1C) includes multiple white solidstate emitting (S) 6 ₁ and 6 ₂. Although the two white light emittingelements could emit the same color temperature of white light, in thisexample, the two elements 6 emit white light of two different colortemperatures.

The system 1C is generally similar to the system 1A discussed above, andsimilarly numbered elements have similar structures, arrangements andfunctions. However, in the system 1C the first solid state lightemitting element 6 ₁ is a white LED W₁ of a first type, for emittingwhite light of a first color temperature, whereas the second solid statelight emitting element 6 ₂ is a white LED W₂ of a second type, foremitting white light of a somewhat different second color temperature.Controlled combination of the two types of white light within the cavity2 allows for some color adjustment, to achieve a color temperature ofthe combined light output C that is somewhere between the temperaturesof the two white lights, depending on the amount of each white lightprovided by the two elements 6 ₁ and 6 ₂.

The system 1C implements a passive detection scheme, similar to that ofthe system 1B of FIG. 1B. In this example, the system 1C includes adetector 9 coupled to the cavity 2 to receive electromagnetic energy ofthe particular wavelength after diffuse reflection within the cavity 2.Assuming that the combined white light from the white solid stateemitting sources (S) 6 ₁ and 6 ₂ includes wavelengths substantiallythroughout the visible portion of the spectrum, the detector 9 would bea type of device that is sensitive to one or more wavelengths outsidethe visible portion of the spectrum, e.g. for sensing near or far IRlight or UV light.

FIG. 1D illustrates another system example 1D. The system 1D is similarto the system 1C discussed above, and similarly numbered elements havesimilar structures, arrangements and functions. However, in the system1D the multiple solid state light emitting elements 6 ₃ are white lightemitters of the same type. Although the actual spectral output of theemitters 6 ₃ may vary somewhat from device to device, the solid statelight emitting elements 6 ₃ are of a type intended to emit white lightof substantially the same color temperature. The diffuse processing andcombination of light from the solid state white light emitting elements6 ₃ provides a virtual source of uniform white light output over thearea of the aperture 5, much like in the other embodiment of FIG. 1C.However, because the emitting elements 6 ₃ all emit white light ofsubstantially the same color temperature, the combined light C also hassubstantially the same color temperature.

Although applicable to all of the illustrated embodiments, it may behelpful at this point to consider an advantage of the fixture geometryand diffusely reflective processing by the cavity 2 in a bit moredetail, with regard to the white light examples, particularly that ofFIG. 1D.

The solid state light emitting elements 6 represent point sources. Theactual area of light emission from each element 6 is relatively small.The actual light emitting chip area may be only a few square millimetersor less in area. The LED packaging often provides some diffusion, butthis only expands the source area a bit, to tens or hundreds ofmillimeters. Such a concentrated point source output may be potentiallyhazardous if viewed directly. Where there are multiple solid statesources, when viewed directly, the sources appear as multiple brightlight point sources.

The processing within the cavity 2, however, combines and spreads thelight from the solid state light emitting elements 6 for virtual sourceoutput via the much larger area of the aperture 5. An aperture 5 with atwo (2) inch radius represents a virtual source area of 12.6 squareinches. Although the aperture 5 may still appear as a bright virtuallight source, the bright light over the larger area will often representa reduced hazard. The integration by the optical cavity also combinesthe point source light to form a uniform distribution at the virtualsource. The uniform distribution extends over the optical output area ofthe virtual source, the area of aperture 5 in the example, which islarger than the combined areas of outputs of the point sources of lightfrom the solid state emitters 6. The intensity at any point in thevirtual source will be much less that that observable at the point ofemission of one of the solid state light emitting elements 6. In theexamples, the cavity 2 serves as an optical processing element todiffuse the light from the solid state light emitting element 6 over thevirtual source output area represented by the aperture 5, to produce alight output through the optical output area that is sufficientlyuniform across the virtual source area as to appear as an unpixelatedlight output.

The system 1D implements a passive detection scheme, similar to that ofthe system 1B of FIG. 1B. In this example, the system 1D includes adetector 9 coupled to the cavity 2 to receive electromagnetic energy ofthe particular wavelength after diffuse reflection within the cavity 2.Assuming that the white light from the white solid state emittingsources (S) 6 ₃ includes wavelengths substantially throughout thevisible portion of the spectrum, the detector 9 would be a type ofdevice that is sensitive to one or more wavelengths outside the visibleportion of the spectrum, e.g. for sensing near or far IR light or UVlight.

FIGS. 1E and 1F illustrate additional system examples, which include atleast one solid state light emitting element for emitting light outsidethe visible portion of the electromagnetic spectrum. The system 1E issimilar to the systems discussed above, and similarly numbered elementshave similar structures, arrangements and functions. In the system 1E,one solid state light emitting element 6 ₄ emits visible light, whereasanother solid state light emitting element 6 ₅ emits ultraviolet (UV)light. The cavity 2 reflects, diffuses and combines visible and UV lightfrom the solid state light emitting element 6 ₄ and 6 ₅, in essentiallythe same manner as in the earlier visible light examples.

The system also includes a detector 9. In this case, the source 9 may besensitive to energy of the wavelength produced by the UV source 6 ₅, asthat energy includes one or more light wavelengths outside the spectrumproduced by the source 6 ₄ used for the visible illuminationapplication. In this example, the source 6 ₅ is coupled to supplyelectromagnetic energy of the particular wavelength into the opticalintegrating cavity 2 in such a manner that substantially all energy ofthat wavelength emitted from the source 6 ₅ reflects diffusely at leastonce within the interior of the optical integrating cavity 2 beforeemission with the diffusely reflected visible light C through theoptical aperture 5 toward the region or area to be illuminated by thesystem 1E. If the detector 9 were coupled to receive light within thecavity, as in the earlier embodiments, it would be flooded by the lightfrom the source 6 ₅ that is inside the cavity and not yet emittedthrough the aperture 5 and could not sense reflected light of thatwavelength coming back from the illuminated region. Hence, the detector9 in this example is located separately and not coupled to the cavity 2.The detector 9 detects reflected UV electromagnetic energy from theilluminated region. After reflection off of a person or object in theregion, the reflected UV light reaches the detector 9 without passage ofthe reflected UV light energy through the optical aperture 5.

The system 1F is similar to the systems discussed above, particularlythe system 1B of FIG. 1B, and similarly numbered elements have similarstructures, arrangements and functions. In the system 1F, one solidstate light emitting element 6 ₆ emits visible light for visibleillumination or other lighting applications, whereas another solid statelight emitting element 6 ₇ emits infrared (IR) light. The 1R light fromelement 6 ₇ is outside the spectrum of light produced by the solid statelight emitting element 6 ₆. The cavity 2 reflects, diffuses and combinesvisible and IR light from the solid state light emitting elements 6 ₆and 6 ₇ in essentially the same manner as in the earlier examples.

The detector 9 in this example is mounted separately so as to notreceive light via the cavity 2. Instead, the detector 9 detectsreflected or separately generated electromagnetic energy from theilluminated region. After reflection off of a person or object in theregion, the reflected light reaches the detector 9 without passage ofthe reflected light energy through the optical aperture 5. The detector9 could detect a wavelength of visible light that is absent from thelight produced by source 6 ₆, the detector 9 may detect IR lightproduced by source 6 ₇ reflected back from persons or objects within thearea illuminated by the system 1F, or the detector 9 may detect IR orother light of a wavelength different from that produced by source 6 ₇.

In an example where the control 7 controls operation of the system inresponse to the detection signal, the detector 9 would typically detectIR light of the same wavelength(s) as produced by the solid state lightemitting element 6 ₇. If the reflected IR light of that spectralcharacteristic from the illuminated region changes by a predeterminedamount, the controller would change the operating condition/state of thesystem 1F. IR detection, whether passive or active, can be used as anoccupancy detection. When a person enters the illuminated area (whenpreviously unoccupied), the controller turns ON the visible lightemissions or turns-up the intensity. The controller keeps the visiblelight ON while the area is occupied. After all persons leave, and thearea is unoccupied for more than some minimal time, the controller turnsdown or OFF the visible light output.

The illustrated IR emission and detection of FIG. 1F may be used in adifferent manner, for data communications. It is possible to modulatethe operations of the IR solid state light emitting element 6 ₇ to carrydata. Typically, the IR solid state light emitting element 6 ₇ wouldemit modulated light of a first infrared wavelength. A receiver (notshown) in the illuminated area would pick up that light, demodulate itand recover the data. The detector 9 in turn would sense IR light of asecond infrared wavelength that is different from the first infraredwavelength. In this way, the detector would not be sensitive toreflections of the modulated IR light from the light emitting element 6₇. The detector 9 would supply its sensing signal to the control circuit7. Although the control might control system operation in response tothat signal, assume now that the control processes the signal for adifferent purpose, to recover data. A transmitter (not shown) wouldmodulate IR light of the wavelength that the detector 9 is configured tosense with data. The detection signal from the detector 9 could bedemodulated to capture that data.

The data communications capabilities offered by the IR solid state lightemitting element 6 ₇ and the IR sensitive detector 9 could be used fortwo-way communication of data regarding system operation, e.g. remotecontrol and associated responsive signaling. However, thesecommunications could enable use of the system for more general two-waydata communications, e.g. as a two-way wireless interface to a datanetwork.

In the example of FIG. 1F, the detector 9 is shown as a separate elementfor sensing light reflected or generated in the illuminate regionwithout passing through the aperture from the reflection point orsource. However, if there is sufficient wavelength separation betweenthe wavelength emitted by light emitting element 6 ₇ and the wavelengthsensed by the detector 9, the detector 9 would be coupled to receivelight reflected within the cavity, in a manner similar to that in theexample of FIG. 1.

Applications are also disclosed that utilize sources of two, three ormore different types of light sources, that is to say solid state lightsources that produce electromagnetic energy of two, three or moredifferent spectral characteristics. Many such examples include sourcesof visible red (R) light, visible green (G) light and visible blue (B)light or other combinations of primary colors of light. Controlledamounts of light from primary color sources can be combined to producelight of many other visible colors, including various temperatures ofwhite light. It may be helpful now to consider several more detailedexamples of lighting systems using solid state light emitting elements.A number of the examples, starting with that of FIG. 2 use RGB LEDs orsimilar sets of devices for emitting three or more colors of visiblelight for combination within the optical integrating cavity and virtualsource emission.

FIG. 2 is a cross-sectional illustration of a radiant energydistribution apparatus or system 20. For task lighting applications andthe like, the apparatus emits light in the visible spectrum, althoughthe system 20 may be used for lumination applications and/or withemissions in or extending into the infrared and/or ultraviolet portionsof the radiant energy spectrum.

The illustrated system 20 includes an optical cavity 11 having adiffusely reflective interior surface, to receive and diffusely processradiant energy of different colors/wavelengths. The cavity 11 may havevarious shapes. The illustrated cross-section would be substantially thesame if the cavity 11 is hemispherical or if the cavity issemi-cylindrical with the cross-section taken perpendicular to thelongitudinal axis. The optical cavity 11 in the examples discussed belowis typically an optical integrating cavity.

The disclosed apparatus may use a variety of different structures orarrangements for the optical integrating cavity, several examples ofwhich are discussed below. At least a substantial portion of theinterior surface(s) of the cavity exhibit(s) diffuse reflectivity. It isdesirable that the cavity surface have a highly efficient reflectivecharacteristic, e.g. a reflectivity equal to or greater than 90%, withrespect to the relevant wavelengths. In the example of FIG. 2, thesurface is highly diffusely reflective to energy in the visible,near-infrared, and ultraviolet wavelengths.

The cavity 11 may be formed of a diffusely reflective plastic material,such as a polypropylene having a 97% reflectivity and a diffusereflective characteristic. Such a highly reflective polypropylene isavailable from Ferro Corporation—Specialty Plastics Group, Filled andReinforced Plastics Division, in Evansville, Ind. Another example of amaterial with a suitable reflectivity is SPECTRALON. Alternatively, theoptical integrating cavity may comprise a rigid substrate having aninterior surface, and a diffusely reflective coating layer formed on theinterior surface of the substrate so as to provide the diffuselyreflective interior surface of the optical integrating cavity. Thecoating layer, for example, might take the form of a flat-white paint orwhite powder coat. A suitable paint might include a zinc-oxide basedpigment, consisting essentially of an uncalcined zinc oxide andpreferably containing a small amount of a dispersing agent. The pigmentis mixed with an alkali metal silicate vehicle-binder, which preferablyis a potassium silicate, to form the coating material. For moreinformation regarding the exemplary paint, attention is directed to U.S.patent application Ser. No. 09/866,516, which was filed May 29, 2001, byMatthew Brown, which issued as U.S. Pat. No. 6,700,112 on Mar. 2, 2004.

For purposes of the discussion, the cavity 11 in the apparatus 20 isassumed to be hemispherical. In the example, a hemispherical dome 13 anda substantially flat cover plate 15 form the optical cavity 11. At leastthe interior facing surfaces of the dome 13 and the cover plate 15 arehighly diffusely reflective, so that the resulting cavity 11 is highlydiffusely reflective with respect to the radiant energy spectrumproduced by the device 20. As a result, the cavity 11 is an integratingtype optical cavity. Although shown as separate elements, the dome andplate may be formed as an integral unit. For example, rectangularcavities are contemplated, in which the dome and plate are elements of aunitary extruded member.

The optical integrating cavity 11 has an aperture 17 for allowingemission of combined radiant energy. In the example, the opticalaperture 17 is a passage through the approximate center of the coverplate 15, although the aperture may be at any other convenient locationon the plate 15 or the dome 13. Because of the diffuse reflectivitywithin the cavity 11, light within the cavity is integrated or combinedbefore passage out of the aperture 17. As in the earlier examples, thisdiffuse processing of light produces a virtual light source at theaperture 17. If as illustrated the actual sources emit light of two ormore different colors, the virtual source appears as a source of a colorof light that results from the combination of the colors from the actualsources.

The integration produces a highly uniform light distribution across theaperture 17 of the cavity 11, which forms the virtual output area andoften forms all or a substantial part of the output area of the fixture.Typically, the distribution of light across the aperture 17 issubstantially Lambertian. During operation, when viewed from the areailluminated by the combined light, the aperture 17 appears to be a lightsource of substantially infinite depth of the combined color of light.Also, the visible intensity is spread uniformly across the aperture 17,as opposed to individual small point sources as would be seen if the oneor more of the light emitting elements were directly visible. Thisconversion to a virtual source, by spreading of the light over theaperture area, reduces or eliminates hazards from direct view of intensesolid state point sources. The virtual source fixture output isrelatively uniform across the apparent output area of the virtualsource, e.g. across the optical aperture 17 of the cavity 11. Typically,the virtual source light output exhibits a relatively lowmaximum-to-minimum intensity ratio across the area of the aperture 17.In the example, the virtual source light output exhibits amaximum-to-minimum ratio of 2 to 1 (2:1) or less over substantially theentire virtual source optical output area represented by the aperture17.

In the examples, the apparatus 20 is shown emitting the radiant energydownward from the virtual source, that is to say downward through theaperture 17, for convenience. However, the apparatus 20 may be orientedin any desired direction to perform a desired application function, forexample to provide visible luminance to persons in a particulardirection or location with respect to the fixture or to illuminate adifferent surface such as a wall, floor or table top. Also, the opticalintegrating cavity 11 may have more than one aperture 17, for example,oriented to allow emission of integrated light in two or more differentdirections or regions.

The apparatus 20 also includes solid state light emission sources ofradiant energy of different wavelengths. In this example, the solidstate sources are LEDs 19, two of which are visible in the illustratedcross-section. The LEDs 19 supply radiant energy into the interior ofthe optical integrating cavity 11. As shown, the points of emission intothe interior of the optical integrating cavity are not directly visiblethrough the aperture 17. Direct emissions from the LEDs 19 are directedtoward the diffusely reflective inner surface of the dome 13, so as todiffusely reflect at least once within the cavity 11 before emission inthe combined light passing out of the cavity through the aperture 17. Atleast the two illustrated LEDs 19 emit radiant energy of differentwavelengths, e.g. Red (R) and Green (G). Additional LEDs of the same ordifferent colors may be provided. The cavity 11 effectively integratesthe energy of different wavelengths, so that the integrated or combinedradiant energy emitted through the aperture 17 forms a virtual source oflight that includes the radiant energy of all the various wavelengths inrelative amounts substantially corresponding to the relative amounts ofinput into the cavity 11 from the respective LEDs 19.

The source LEDs 19 can include LEDs of any color or wavelength.Typically, an array of primary color LEDs for a visible lightapplication includes at least red, green, and blue LEDs. The integratingor mixing capability of the cavity 11 serves to project light of anycolor, including white light, by adjusting the intensity of the varioussources coupled to the cavity. Hence, it is possible to control colorrendering index (CRI), as well as color temperature. The system 20 workswith the totality of light output from a family of LEDs 19. However, toprovide color adjustment or variability, it is not necessary to controlthe output of individual LEDs, except as they contribute to thetotality. For example, it is not necessary to modulate the LED outputs,although modulation may be used if desirable for particularapplications. Also, the distribution pattern of the individual LEDs andtheir emission points into the cavity are not significant. The LEDs 19can be arranged in any manner to supply radiant energy within thecavity, although it is preferred that direct view of the LEDs fromoutside the fixture is minimized or avoided.

In this example, light outputs of the LED sources 19 are coupleddirectly to openings at points on the interior of the cavity 11, to emitradiant energy directly into the interior of the optical integratingcavity. Direct emissions are aimed at a reflective surface of thecavity. The LEDs 19 may be located to emit light at points on theinterior wall of the element 13, although preferably such points wouldstill be in regions out of the direct line of sight through the aperture17. For ease of construction, however, the openings for the LEDs 19 areformed through the cover plate 15. On the plate 15, the openings/LEDsmay be at any convenient locations. From such locations, all orsubstantially all of the direct emissions from the LEDs 19 impact on theinternal surface of the dome 13 and are diffusely reflected.

The exemplary system 20 also includes a sensor or detector 16, forsensing a characteristic of the reflected light from within the interiorof the cavity 11. The sensor 16, for example, may detect intensity ofthe combined light in the cavity 11. As another example, the sensor mayprovide some indication of the spectral characteristic of the combinedlight in the cavity 11. The detector 16 operates as a feedback sensor,for use in controlling system operations. Although the detector 16 couldalso sense intensity of one or more additional wavelengths (analogous tooperation of detector 9 in the earlier examples), typically, theintensity and/or spectral characteristic sensed by detector 16 is thatof the light produced by the diffuse processing of the light from theLEDs 19 within the cavity 11 for the illumination application. In sucharrangements, the signal from the detector 16 is used for feedbackpurposes.

The exemplary system 20 also includes a sensor or detector 18 fordetecting an amount (e.g. intensity) of electromagnetic energy of awavelength that is absent from the light produced by the LEDs 19 and/orthe diffuse processing of the light from the LEDs 19 within the cavity11. In this example, the RGB LEDs 19 produce visible light, and thecombined light produced by diffuse reflection of the light from the LEDs19 within the cavity 11 is visible light. It is intended that adjustmentof the amounts of light from the LEDs will enable selection of thespectral characteristic of the visible light output of the system over asubstantial range of the visible light portion of the electromagneticspectrum. Hence, the detector 18 is of a type or configuration forsensing at least one wavelength outside of the visible light portion ofthe electromagnetic spectrum. Although the detector 18 might sense UVlight or other non-visible wavelengths, in the example of system 20, thedetector 18 senses IR light energy in the near IR range or in the far IRrange.

The detector 18 is coupled to receive light from within or on a wall ofthe cavity 11 so that the detector 18 senses a characteristic ofelectromagnetic energy diffusely reflected within the cavity 11. Thedetector may be located at or otherwise coupled to any convenient pointon or within the cavity 11, although typically the point is on a wall ofthe cavity and located so that light entering through the aperture 17reflects diffusely one or more times within the cavity before reachingthe point of coupling to the detector 18. Since the detector 18 senses awavelength not present in the spectrum of light output by the LEDs 19,the detector 18 is responsive to energy of that wavelength that entersthe cavity 11 via the aperture 17 and reflects off the surface(s) of thecavity 11.

The apparatus 20 also includes a control circuit 21 coupled to the LEDs19 for establishing output intensity of radiant energy of each of theLED sources. The control circuit 21 is responsive to detection signalssupplied by the detectors 16 and 18. The control circuit 21 typicallyincludes a power supply circuit coupled to a source, shown as an ACpower source 23. The control circuit 21 also includes an appropriatenumber of LED driver circuits for controlling the power applied to eachof the different color LEDs 19 and thus the amount of radiant energysupplied to the cavity 11 for each different wavelength. It is possiblethat the power could be modulated to control respective light amountsoutput by the LEDs 19, however, in the examples, LED outputs arecontrolled by controlling the amount of power supplied to driverespective LEDs. Such control of the amount of light emission of thesources sets a spectral characteristic of the combined radiant energyemitted through the aperture 17 of the optical integrating cavity. Thecontrol circuit 21 may be responsive to a number of different controlinput signals, for example, to one or more user inputs as shown by thearrow in FIG. 2. Specific examples of the control circuitry arediscussed in more detail later.

The system 20 also includes a source 24 of IR light, that is to say ofat least one wavelength absent from the light produced by the LEDs 19and the combined light output emitted through the aperture 17. Thesource 24 may emit light of a different wavelength from that sensed bythe detector 18, as discussed earlier, but in this example, the IRsource 24 emits light of a wavelength that the detector 18 will sense.The IR source 24 may be mounted on or near the fixture but outside thecavity 11, or the IR source 24 may be mounted at a different location.The IR source could be directed from the illuminated area toward theaperture for some applications; but in the example, the source 24 isoriented to direct its output away from the fixture and into a portionof the area illuminated by the fixture. Hence, the IR light from thesource 24 illuminates at least a portion of a region intended to beilluminated by the combined light output from the aperture 17. One ormore additional sources 24 (shown in dotted line form) may also beprovided.

The aperture 17 may serve as the system output, directing integratedcolor light of relatively uniform intensity distribution to a desiredarea or region to be illuminated. Although not shown in this example,the aperture 17 may have a grate, lens or diffuser (e.g. a holographicelement) to help distribute the output light and/or to close theaperture against entry of moisture of debris. For some applications, thesystem 20 includes an additional downstream optical processing element,such as deflector, diffuser, filter or the like.

The exemplary apparatus 20 shown in FIG. 2 comprises a deflector 25, asthe additional optical processing element. The deflector 25 has areflective inner surface 29, to efficiently direct most of the lightemerging from a light source at aperture C into a relatively narrowfield of view. A small opening at a proximal end of the deflector iscoupled to the aperture 17 of the optical integrating cavity 11. Thedeflector 25 has a larger opening 27 at a distal end thereof. Althoughother shapes may be used, the deflector 25 is conical. The angle anddistal opening of the conical deflector 25 define an angular field ofradiant energy emission from the apparatus 20. Although not shown, thelarge opening of the deflector may be covered with a transparent plateor lens, or covered with a grating, to prevent entry of dirt or debristhrough the cone into the system and/or to further process the outputradiant energy.

The deflector 25 may have a variety of different shapes, depending onthe particular lighting application. In the example, where cavity 11 ishemispherical, the cross-section of the conical deflector is typicallycircular. However, the deflector may be somewhat oval in shape. Inapplications using a semi-cylindrical cavity, the deflector may beelongated or even rectangular in cross-section. The shape of theaperture 17 also may vary, but will typically match the shape of thesmall end opening of the deflector 25. Hence, in the example, theaperture 17 would be circular. However, for a device with asemi-cylindrical cavity and a deflector with a rectangularcross-section, the aperture may be rectangular.

The deflector 25 comprises a reflective interior surface 29 between thedistal end and the proximal end. In some examples, at least asubstantial portion of the reflective interior surface 29 of the conicaldeflector exhibits specular reflectivity with respect to the integratedradiant energy. As discussed in U.S. Pat. No. 6,007,225, for someapplications, it may be desirable to construct the deflector 25 so thatat least some portion(s) of the inner surface 29 exhibit diffusereflectivity or exhibit a different degree of specular reflectivity(e.g., quasi-secular), so as to tailor the performance of the deflector25 to the particular application. For other applications, it may also bedesirable for the entire interior surface 29 of the deflector 25 to havea diffuse reflective characteristic. In such cases, the deflector 25 maybe constructed using materials similar to those taught above forconstruction of the optical integrating cavity 11.

In the illustrated example, the large distal opening 27 of the deflector25 is roughly the same size as the cavity 11. In some applications, thissize relationship may be convenient for construction purposes. However,a direct relationship in size of the distal end of the deflector and thecavity is not required. The large end of the deflector may be larger orsmaller than the cavity structure. As a practical matter, the size ofthe cavity is optimized to provide the integration or combination oflight colors from the desired number of LED sources 19. The size, angleand shape of the deflector determine the area that will be illuminatedby the combined or integrated light emitted from the cavity 11 via theaperture 17 and the field of view of the cavity for purposes ofreceiving IR light for sensing by detector 18.

In the example, each solid state source of radiant energy of aparticular wavelength comprises one or more light emitting diodes(LEDs). Within the chamber, it is possible to process light receivedfrom any desirable number of such LEDs. Hence, in several examplesincluding that of FIG. 2, the sources may comprise one or more LEDs foremitting light of a first color, and one or more LEDs for emitting lightof a second color, wherein the second color is different from the firstcolor. Each LED represents a point source of a particular color, whichin the RGB example, is one of three primary colors. The diffuseprocessing converts the point source lights to a single combined virtualsource light at the aperture. In a similar fashion, the apparatus mayinclude additional sources comprising one or more LEDs of a third color,a fourth color, etc.; and the diffuse processing combines thoseadditional lights into the virtual source light output. To achieve thehighest color rendering index (CRI) at the virtual source output, theLED array may include LEDs of various wavelengths that cover virtuallythe entire visible spectrum. Examples with additional sources ofsubstantially white light are discussed later.

Each of the detectors 16 and 18 supplies a detection signal to thecontrol circuit 21. The detector 16 provides feedback as to theoperation of the system 20, and the controller in circuit 21 uses thatsignal to adjust one or more operation parameters of the LED outputs, ina manner intended to achieve and maintain intensity and/or color outputsettings. As noted above, the detector 18 senses an amount of energy ofthe particular wavelength that is received back from the illuminatedarea and reflected within the cavity 11. Although the controller couldprocess or use the signal in other ways (e.g. to receive data for remotecontrol or communication purposes), in this example, the controller 21controls one or more operations of the system 20 in response to thedetection signal from the detector 18. The IR light from source 24 andthe attendant IR reflection sensed by detector 18 for example mayprovide a system for active detection of whether or not the areailluminated by the system is occupied. Hence, in response to occupancyconditions indicated by the signal from the detector 18, the controlcircuit 21 can turn the LEDs 19 ON and OFF, or the controller may varythe amount of output (while ON) of one or more colors of LEDs to adjustthe output intensity and/or color in some manner.

A number of different examples of control circuits are discussed below.In one example, the control circuitry comprises a color feedback sensorcoupled to detect color distribution in the integrated radiant energy.Associated logic circuitry, responsive to the detected colordistribution, controls the output intensity of the various LEDs, so asto provide a desired color distribution in the integrated radiantenergy. In an example using sleeper LEDs, the logic circuitry isresponsive to the detected color distribution to selectively activatethe inactive light emitting diodes as needed, to maintain the desiredcolor distribution in the integrated radiant energy.

The inventive devices have numerous applications, and the outputintensity and spectral characteristic may be tailored and/or adjusted tosuit the particular application. For example, the intensity of theintegrated radiant energy emitted through the aperture may be at a levelfor use in a luminance application or at a level sufficient for a tasklighting application or other type of general lighting application. Anumber of other control circuit features also may be implemented. Forexample, the control circuit 21 may turn ON/OFF the LEDs based onoccupancy in response to the signal from detector 18, but while ON,maintain a set color characteristic in response to color feedback from asensor 16. The control circuitry 21 may also include a temperaturesensor. In such an example, the logic circuitry is also responsive tothe sensed temperature, e.g. to reduce intensity of the source outputsto compensate for temperature increases. The control circuitry 21 mayinclude a user interface device or receive signals from a separate userinterface device, for manually setting the desired spectralcharacteristic. For example, an integrated user interface might includeone or more variable resistors or one or more dip switches directlyconnected into the control circuitry, to allow a user to define orselect the desired color distribution and/or intensity.

Communication in support of or in addition to the control functions alsois envisioned. For example, the control circuitry may include a datainterface coupled to the logic circuitry, for receiving data definingthe desired intensity and/or color distribution. Such an interface wouldallow input of control data from a separate or even remote device, suchas a personal computer, personal digital assistant or the like. A numberof the devices, with such data interfaces, may be controlled from acommon central location or device. Such a communication interface to thecontrol circuitry may also provide a link to a network, e.g. when thesource 24 and detector 18 are used for two-way IR transport of wirelessdata signals.

The control may be somewhat static, e.g. to set the desired colorreference index or desired color temperature and the overall intensity,and leave the device set-up in that manner for an indefinite periodunless or until a detected change in occupancy status. In the ON state,the apparatus also may be controlled dynamically, for example, toprovide special effects lighting. Where a number of the devices arearranged in a large two-dimensional array, dynamic control of color andintensity of each unit could even provide a video display capability,for example, for use as a “Jumbo Tron” view screen in a stadium or thelike. In product lighting or in personnel lighting (for studio ortheater work), the lighting can be adjusted for each product or personthat is illuminated. Also, such light settings are easily recorded andreused at a later time or even at a different location using a differentsystem.

To appreciate the features and examples of the control circuitryoutlined above, it may be helpful to consider a more detailed example ofthe circuitry with reference to an appropriate diagram. FIG. 3 is ablock diagram of exemplary circuitry for the sources and associatedcontrol circuit, providing digital programmable control, which may beutilized with a light integrating fixture of the type described above.As discussed below, the illustrated circuitry also includes an IR sourceand IR detector corresponding to those of the system 20 of FIG. 2,although similar circuitry could be used with sources and detectors foremitting/sensing other wavelengths as outlined in several of theexamples above.

In this circuit example (FIG. 3), the solid state sources of radiantenergy of the various types take the form of an LED array 111. Arrays ofone, two or more colors may be used. The illustrated array 111 comprisestwo or more LEDs of each of three primary colors, red green and blue,represented by LED blocks 113, 115 and 117. For example, the array maycomprise six red LEDs 113, three green LEDs 115 and three blue LEDs 117.

The LED array 111 in this example also includes a number of additionalor “other” LEDs 119. There are several types of additional LEDs that areof particular interest in the present discussion. One type of additionalLED provides one or more additional wavelengths of radiant energy forintegration within the chamber for use in the illumination application.The additional wavelengths may be in the visible portion of the lightspectrum, to allow a greater degree of color adjustment.

The second type of additional LED that may be included in the system isa “sleeper” LED. Sleeper LEDs provide redundant light generationcapacity, particularly with respect to light used for the illuminationapplication. Some LEDs would be active, whereas the sleepers would beinactive, at least during initial operation. Using the circuitry of FIG.3 as an example, the Red LEDs 113, Green LEDs 115 and Blue LEDs 117might normally be active. The LEDs 119 would be sleeper LEDs, typicallyincluding one or more LEDs of each color used in the particular system.The controller activates sleepers on an as-needed basis, e.g. tocompensate for declining LED performance as indicated by a feedbacksignal from a detector.

The third type of other LED of interest is a white LED. The entire array111 may consist of white LEDs of one, two or more color temperatures.For white lighting applications using primary color LEDs (e.g. RGBLEDs), one or more white LEDs provide increased intensity; and theprimary color LEDs then provide light for color adjustment and/orcorrection.

The ‘other’ LEDs 119 could produce energy of an additional wavelengthnot provided by the LEDs 113, 115 and 117 for the illuminationapplication, e.g. one or more wavelengths outside the visible spectrum,such as in the infrared (IR) range or the ultraviolet (UV) range, as insome of the earlier examples. For discussion here, however, it isassumed that all of the LEDs in the array 111 emit visible light intothe chamber and thus correspond to the LEDs 19 in the system 20 of FIG.2.

The illustrated circuitry, however, also includes one or more sources ofelectromagnetic energy of at least one wavelength not produced by theLED array 111 or the processing of the lights from the LED array 111within the optical integrating cavity. As in the example of FIG. 2, theadditional source of such electromagnetic energy produces infrared (IR)light. Although other IR sources could be used, in the example, thecircuitry includes one or more IR LEDs 118, which correspond to the IRsources 24 in the example of FIG. 2. Although not shown, there may beone or more IR sleeper LEDs, as well. The IR LEDs 118 may be coupled tothe cavity or coupled to emit light outside the cavity (see FIGS. 1F and2, respectively).

The electrical components shown in FIG. 3 also include an LED controlsystem 120. The system 120 includes driver circuits for the variousLEDs, as well as a microcontroller. The driver circuits supplyelectrical current to the respective LEDs 113, 115, 117 and 119 of thearray 111 to cause the LEDs of the array to emit light. The drivercircuit 121 drives the Red LEDs 113, the driver circuit 123 drives thegreen LEDs 115, and the driver circuit 125 drives the Blue LEDs 117. Ina similar fashion, when active, the driver circuit 127 provideselectrical current to the other LEDs 119. If the other LEDs provideanother color of light, and are connected in series, there may be asingle driver circuit 127. If the LEDs are sleepers, it may be desirableto provide a separate driver circuit 127 for each of the LEDs 119 or atleast for each set of LEDs of a different color.

Since the source of the IR light comprises one or more LEDs 118, the LEDcontrol system 120 also includes a LED driver circuit 128 for providingelectrical current to the IR LEDs 118. The microcontroller controls thedriver circuits, including the driver circuit 128 for the IR LEDs 118,to establish respective output levels from the various LEDs.

Control of the LED outputs could be controlled by selective modulationof the drive signals applied to the various LEDs. In the example, theintensity of the emitted light of a given LED is proportional to thelevel of current supplied by the respective driver circuit. The currentoutput of each driver circuit is controlled by the higher level logic ofthe system. In this digital control example, that logic is implementedby a programmable microcontroller 129, although those skilled in the artwill recognize that the logic could take other forms, such as discretelogic components, an application specific integrated circuit (ASIC),etc. Although not separately shown, digital to analog converters (DACs)may be utilized to convert control data outputs from the microcontroller129 to analog control signal levels for control of the LED drivercircuits.

The LED driver circuits and the microcontroller 129 receive power from apower supply 131, which is connected to an appropriate power source (notseparately shown). For most task-lighting applications and the like, thepower source will be an AC line current source, however, someapplications may utilize DC power from a battery or the like. The powersupply 129 converts the voltage and current from the source to thelevels needed by the driver circuits 121-128 and the microcontroller129.

A programmable microcontroller typically includes or has coupled theretorandom-access memory (RAM) for storing data and read-only memory (ROM)and/or electrically erasable read only memory (EEROM) for storingcontrol programming and any pre-defined operational parameters, such aspre-established light ‘recipes’ or ‘routines.’ The microcontroller 129itself comprises registers and other components for implementing acentral processing unit (CPU) and possibly an associated arithmeticlogic unit. The CPU implements the program to process data in thedesired manner and thereby generates desired control outputs.

The microcontroller 129 will typically be on at all times that thesystem circuitry is connected to power, whether the system is emittingvisible light or not. For at least some applications, such as where theIR is emitted and sensed for room or area occupancy detection, themicrocontroller 129 is programmed to control the LED driver circuit 128so that the IR LEDs 118 are substantially always active, although theoutput may be modulated if desirable.

The microcontroller 129 is programmed to control the LED driver circuits121-127 to set the individual output intensities of the LEDs to desiredlevels, so that the combined light emitted from the aperture of thecavity has a desired spectral characteristic and a desired overallintensity. The microcontroller 129 may be programmed to convert colorsettings, input for example by a user, into appropriate intensity and/ormodulation values for the various LED drive currents. Themicrocontroller 129 may be programmed to essentially establish andmaintain or preset a desired ‘recipe’ or mixture of the availablewavelengths provided by the LEDs used in the particular system. For someapplications, the microcontroller may work through a number of settingsover a period of time in a manner defined by a dynamic routine. Themicrocontroller 129 receives control inputs or retrieves a storedroutine specifying the particular ‘recipe’ or mixture, as will bediscussed below. To insure that the desired mixture is maintained, themicrocontroller 129 receives a color feedback signal from an appropriatecolor sensor. The microcontroller may also be responsive to a feedbacksignal from a temperature sensor, for example, in or near the opticalintegrating cavity.

The electrical system will also include one or more control inputs 133for inputting information instructing the microcontroller 129 as to thedesired operational settings. A number of different types of inputs maybe used and several alternatives are illustrated for convenience. Agiven installation may include a selected one or more of the illustratedcontrol input mechanisms.

As one example, user inputs may take the form of a number ofpotentiometers 135. The number would typically correspond to the numberof different light wavelengths provided by the particular LED array 111.The potentiometers 135 typically connect through one or more analog todigital conversion interfaces provided by the microcontroller 129 (or inassociated circuitry). To set the parameters for the integrated lightoutput, the user adjusts the potentiometers 135 to set the intensity foreach color. The microcontroller 129 senses the input settings andcontrols the LED driver circuits accordingly, to set correspondingintensity levels for the LEDs providing the light of the variouswavelengths.

Another user input implementation might utilize one or more dip switches137. For example, there might be a series of such switches to input acode corresponding to one of a number of recipes or to a stored dynamicroutine. The memory used by the microcontroller 129 would store thenecessary intensity levels for the different color LEDs in the array 111for each recipe and/or for the sequence of recipes that make up aroutine. Based on the input code, the microcontroller 129 retrieves theappropriate recipe from memory. Then, the microcontroller 129 controlsthe LED driver circuits 121-127 accordingly, to set correspondingintensity levels for the LEDs 113, 115, 117 and 119 providing the lightof the various wavelengths for the illumination application.

As an alternative or in addition to the user input in the form ofpotentiometers 135 or dip switches 137, the microcontroller 129 may beresponsive to control data supplied from a separate source or a remotesource. For that purpose, some versions of the system will include oneor more communication interfaces. If the IR capabilities of the systemare used for data communications to/from the illuminated area, thecommunication interface would provide a data link for sending and/orreceiving such data via a local or wide area network. One example of ageneral class of such interfaces is a wired interface 139. One type ofwired interface typically enables communications to and/or from apersonal computer or the like, typically within the premises in whichthe fixture operates. Examples of such local wired interfaces includeUSB, RS-232, and wire-type local area network (LAN) interfaces. Otherwired interfaces, such as appropriate modems, might enable cable ortelephone line communications with a remote computer, typically outsidethe premises. Other examples of data interfaces provide wirelesscommunications, as represented by the interface 141 in the drawing.Wireless interfaces, for example, use radio frequency (RF) links. Thewireless communications may be local on-premises communications,analogous to a wireless local area network (WLAN). Alternatively, thewireless communications may enable communication with a remote deviceoutside the premises, using wireless links to a wide area network, e.g.via a cellular network.

As noted above, the electrical components may also include one or morefeedback sensors 143, to provide system performance measurements asfeedback signals to the control logic, implemented in this example bythe microcontroller 129. A variety of different sensors may be used,alone or in combination, for different applications. In the illustratedexamples, the set 143 of feedback sensors includes a color sensor 145and a temperature sensor 147. Although not shown, other sensors, such asan overall intensity sensor may be used. The sensors are positioned inor around the system to measure the appropriate physical condition, e.g.temperature, color, intensity, etc.

The color sensor 145, for example, is coupled to detect colordistribution in the integrated radiant energy that the cavity producesvia is reflective processing of light from the visible light generatingLEDs 113, 115, 117 and 119. The color sensor 145 may be coupled to senseenergy within the optical integrating cavity, within the deflector (ifprovided) or at a point in the field illuminated by the particularsystem. Various examples of appropriate color sensors are known. Forexample, the color sensor may be a digital compatible sensor, of thetype sold by TAOS, Inc. Another suitable sensor might use the quadrantlight detector disclosed in U.S. Pat. No. 5,877,490, with appropriatecolor separation on the various light detector elements (see U.S. Pat.No. 5,914,487 for discussion of the color analysis).

The associated logic circuitry, responsive to the detected colordistribution, controls the output intensity of the various LEDs, so asto provide a desired color distribution in the integrated radiantenergy, in accord with appropriate settings. In an example using sleeperLEDs, the logic circuitry is responsive to the detected colordistribution to selectively activate the inactive light emitting diodesas needed, to maintain the desired color distribution in the integratedradiant energy. The color sensor measures the color of the integratedradiant energy produced by the system and provides a color measurementsignal to the microcontroller 129. If using the TAOS, Inc. color sensor,for example, the signal is a digital signal derived from a color tofrequency conversion. The TAOs sensor is responsive to instructions fromthe microcontroller 129 to selectively measure overall intensity, Redintensity, Green intensity and Blue intensity.

The temperature sensor 147 may be a simple thermo-electric transducerwith an associated analog to digital converter, or a variety of othertemperature detectors may be used. The temperature sensor is positionedon or inside of the fixture, typically at a point that is near the LEDsor other sources that produce most of the system heat. The temperaturesensor 147 provides a signal representing the measured temperature tothe microcontroller 129. The system logic, here implemented by themicrocontroller 129, can adjust intensity of one or more of the LEDs inresponse to the sensed temperature, e.g. to reduce intensity of thesource outputs to compensate for temperature increases. The program ofthe microcontroller 129, however, would typically manipulate theintensities of the various LEDs so as to maintain the desired colorbalance between the various wavelengths of light used in the system,even though it may vary the overall intensity with temperature. Forexample, if temperature is increasing due to increased drive current tothe active LEDs (with increased age or heat), the controller maydeactivate one or more of those LEDs and activate a corresponding numberof the sleepers, since the newly activated sleeper(s) will providesimilar output in response to lower current and thus produce less heat.

As in the earlier examples, the system of FIG. 3 includes a detector forsensing at least one wavelength of electromagnetic energy that is notcontained in the light generated by the LEDs 113, 115, 117 and 119 (orby the processing of that light within the optical integrating cavity).Although such a detector may detect energy in other spectral regions, inthis circuit example, the system includes an IR detector or sensor 149.The detector may receive IR light directed from the region illuminatedby the system, but for discussion purposes, it is assumed here that theIR sensor 149 is coupled to receive IR light energy via an opticalintegrating chamber, in a manner similar to the detector 18 in theexample of FIG. 2. Any of a variety of available IR sensors may be used.

The sensor 149 generates a detection signal proportional in some knownmanner to the amount of IR light energy reaching the optical input tothe sensor 149. The sensor 149 provides this detection signal to themicrocontroller 129 for processing for example as a pulse train of afrequency proportional to the amount of sensed IR light or as digitizedamplitude signal proportional to the sensed IR light. As discussedearlier, the detected IR light may carry data, in which case themicrocontroller demodulates the detection signal to capture or recoverthe data carried by the IR light, for remote control or datacommunication purposes. For purposes of further discussion here,however, it is assumed that the microcontroller 129 processes thedetection signal from the IR sensor 149 to detect changes in IR lightfrom the illuminated region, in a manner intended to facilitatedetection of occupancy of that region and thus to control systemoperations accordingly. Further discussion of an example of occupancydetection and attendant control refers to FIGS. 4, 5A and 5B.

The occupancy responsive control may control a variety of operatingparameters of the solid state lighting system. For example, themicrocontroller 129 could control color of the combined light output. Asanother example, the processor might set different levels of intensityof the combined light output for different detect occupancies states,e.g. OFF when unoccupied, low-level ON when occupied by one or a smallnumber of people, or ON high intensity when occupied by a large numberof people.

FIG. 4 is a flow chart illustrating the processing of the IR sensorsignal to detect occupancy status and provide responsive ON-OFF control.For purposes of this example, we will assume that the system uses thecircuitry shown in FIG. 3. For the illustrated process example, we willassume that the system is initially in an OFF-state in which it does notemit any visible light (S1). However, the system is connected to powerso that the microcontroller 129 is operative, and in this state, themicrocontroller 129 controls the LED driver 128 for the IR emitter 118to drive that emitter 118 to emit IR light energy into at least aportion of the area or region that is to be illuminated by the virtualsource output light of the system.

In this example, the microcontroller 129 also receives and processes asensing signal from the IR sensor 149. In an example such as that ofFIG. 2, IR light from the emitter would illuminate at least a portion ofthe area or region that is to be illuminated by the virtual sourceoutput light of the system, and IR light reflected from the portion ofthe area would enter the optical integrating cavity through theaperture. In turn, the sensor 149 would receive reflected IR light thathas been diffusely processed within the cavity. In response to thereceived IR light, the IR sensor 149 provides a signal to themicrocontroller 129. The sensing signal represents a measure of anamount of the IR light received by the sensor 149, e.g. its magnitude orintensity. In this manner, the system implements an IR detection step atS2 in FIG. 4.

FIGS. 5A and 5B show simplified graphs of different states of thereflected IR light levels indicated by the sensing signal from thesensor 149. As shown in these graphs, at times when the area or regionthat is to be illuminated by the virtual source output light of thesystem is unoccupied, the amount of reflected IR light will be at a lowambient level.

Based on the IR detection at S2, the microcontroller 129 determines arelationship of the currently detected level of IR light detected by thesensor 149 to a first threshold T1 that microcontroller 129 uses as areference indicating a predetermined change, e.g. to an occupied state.FIG. 5A shows an example of the threshold T1 in relation to typicallevels of reflected IR that might be detected in the unoccupied stateand the occupied state. At step S3 in the process flow of FIG. 4, if thesignal from the IR sensor 149 indicates that the level of detectedreflected IR is below the first threshold T1, then the process flowreturns to the S1, where the microcontroller 129 keeps the system in itsOFF-State. In this way, the process will loop through the detection andthreshold comparison steps S1 to S3 as long as the IR level remainsbelow the first threshold T1 and will keep the system in its OFF-state.

When a person enters the area to be illuminated by the system, theperson will cause an increase in the amount of IR light reflected towardthe light fixture. As a result, the amount of IR light sensed ordetected by the IR sensor 149 will increase. At step S3 in the processflow of FIG. 4, when the signal from the IR sensor 149 indicates thatthe level of detected reflected IR has reached or exceeded (greater thanor equal to) the first threshold T1, then the process flow branches tostep S4. Essentially, the initial detection that the IR level hasreached or exceeded the threshold represents a detection of a change inthat signal of a type that corresponds to a change from an unoccupiedstate to an occupied state, upon entry of one or more people into thearea to be illuminated by the system.

Although the microcontroller 129 could implement other controlfunctions, if desired, in this example, when the processing branches tostep S4, the microcontroller 129 transitions system operation to itsON-state. In the circuitry of FIG. 3, for example, the microcontroller129 activates the drivers 121-127 to turn-ON the LEDs of the array 111,so that the array 111 emits light. The microcontroller 129 will controlthe amounts of light contributed by each of the groups of LEDs 113, 115,117 and 119 in the manner discussed above, and the optical integratingcavity will diffusely process the light from the LEDs 113, 115, 117 and119 of the array 111 to produce a virtual source output of combinedlight, as discussed above relative to FIGS. 1A to 3.

While in the ON-state, the microcontroller 129 continues to control theLED driver 128 for the IR emitter 118 to drive that emitter 118 to emitIR light energy into at least a portion of the area or region that is tobe illuminated by the virtual source output light of the system. Thesystem therefore will detect reflected IR light from the illuminatedarea, at step S5. This detection provides a signal representing theamount of reflected IR light detected by the sensor 149 for processingby the microcontroller 129, essentially as in the OFF-state. However,while occupied, the amount of IR light will be at the higher levelcaused by reflection of IR light by the person or persons occupying thearea, as shown in FIGS. 5A and 5B.

When a person leaves the illuminated area, the amount of reflected IRlight will decrease, and that decrease will be indicated by the sensingsignal from the sensor 149. When the last person leaves, the reflectedIR level will transition from a relatively high state back down to arelatively low ambient level. The system can further control lightoperations in response to detection of such a transition. Hence, in theprocess flow of FIG. 4, at step S6, the microcontroller 129 compares thelevel of reflected IR represented by the detection signal from the IRsensor 149 to a second threshold T2. The second threshold T2 is areference used to indicate a predetermined change, e.g. to an unoccupiedstate. FIG. 5B shows an example of the threshold T2 in relation totypical levels of reflected IR that might be detected in the occupiedstate and the unoccupied state.

At step S6 in the process flow of FIG. 4, if the signal from the IRsensor 149 indicates that the level of detected reflected IR is at orabove (greater than or equal to) the second threshold T2, then theprocess flow returns to the S4, where the microcontroller 129 keeps thesystem in its ON-State. In this way, the process will loop through thedetection and threshold comparison steps S4 to S6 as long as the IRlevel does not fall below the second threshold T2 and will keep thesystem in its light emitting ON-state.

At step S6 in the process flow of FIG. 4, when the signal from the IRsensor 149 indicates that the level of detected reflected IR has droppedbelow (less than) the second threshold T2, then the process flowbranches to step S7. Essentially, the initial detection that the IRlevel has fallen below the threshold represents a detection of a changein that signal of a type that represents a change from an occupied stateto an unoccupied state.

The microcontroller 129 could turn the system OFF at this point.However, as people often enter and exit areas for short times, it isoften desirable to leave the light ON for some interval whileunoccupied, to avoid an excessive number of transitions that some peoplemight find annoying. Hence, when the process flow detects the transitionto the unoccupied state, the step at S7 starts a timer (see also FIG.5B). The timer function may be implemented in any known manner, forexample, so as to count down from a starting value or so as to count upto a maximum value based on a system clock generated or used by themicrocontroller 129. The timer could be a physical device but typicallywould be implemented as a programmed function of the microcontroller129.

At step S8, the microcontroller 129 again compares the IR level to thesecond threshold T2. If the IR level has returned to or exceeded thesecond threshold (greater than or equal to), then it is assumed that thearea has been re-occupied, and processing flows back to the ON-state instep S4.

However, if the IR level as indicated by the sensor signal from IRsensor 149 is below the second threshold T2, i.e. indicating that theilluminated area is unoccupied, then the microcontroller 129 checks thestate of the timer at step S9. If the timer has not yet timed out, thenprocessing returns to step S8. In this way, the processing loops throughsteps S8 and S9 until the IR level rises again (the area again becomesoccupied) or until the timer times out. If the IR level as indicated bythe sensor signal from IR sensor 149 remains below the second thresholdT2 long enough for the timer to time out, then processing branches fromstep S9 to step S11, at which the microcontroller 129 turns OFF thesystem. Hence, when the area has been unoccupied for some measurableperiod, the microcontroller 129 will control the drivers 121-127 toreduce the power supplied to the LEDs 113, 115, 117 and 119 of the array111, so that the array 111 no longer emits light, and of course, so thatthe system consumes substantially less power.

In the preceding example, the microcontroller 129 implemented twothresholds, T1 and T2 in relation to transitions between occupied andunoccupied states of the area illuminated by the system. Those skilledin the art will recognize that a single threshold may be used for bothtransitions. Also, for more complex control algorithms, it may be usefulto apply a larger number of thresholds, e.g. to detect different levelsof occupancy (e.g. different numbers of people occupying the area).

The above discussion of FIG. 3 to 5B related to programmed digitalimplementations of the control logic. Those skilled in the art willrecognize that the control also may be implemented using discrete logiccomponents and/or analog circuitry.

The systems described above have a wide range of applications, wherethere is a desire to set or adjust color and/or intensity provided by alighting fixture. These include task lighting and other general lightingapplications, signal light applications, signage, as well asapplications for illuminating an object or person. Some lightingapplications involve a common overall control strategy for a number ofthe systems. As noted in the discussion of FIG. 3, the control circuitrymay include a communication interface 139 or 141 allowing themicrocontroller 129 to communicate with another processing system. FIG.6 illustrates an example in which control circuits 21 of a number of theradiant energy generation systems with the light integrating anddistribution type fixture communicate with a master control unit 151 viaa communication network 153. The master control unit 151 typically is aprogrammable computer with an appropriate user interface, such as apersonal computer or the like. The communication network 153 may be aLAN or a wide area network, of any desired type. The communicationsallow an operator to control the color and output intensity of all ofthe linked systems, for example to provide combined lighting effects.The commonly controlled lighting systems may be arranged in a variety ofdifferent ways, depending on the intended use of the systems.

The sensing of wavelengths of energy outsides those normally produced bythe solid state light emitters for the illumination operations allowsthe individual fixtures to perform a number of other intelligentfunctions for communication purposes, automation and control of thelighting equipment and/or other systems, monitoring, or the like. Forexample, the network 153 may provide two-way data to and from thesystems 21. In turn, the systems 21 could use light emissions andtransmissions on selected wavelengths (e.g. near and far IR) to providewireless transport of data to devices within the area illuminated by thesystems. Alternatively, the detection might allow the systems to receivecontrol data, to directly control operations or for relay over thenetwork 153 to the master controller 151.

In an application for large area lighting with occupancy control, eachof the systems in FIG. 6 might implement IR emission, sensing andprocessing as discussed above to detect transitions in occupancy state.A system control circuit 21 detecting a change to an occupied statemight turn its light ON and transmit a notification message, to themaster control 151 or directly to the other control circuits 21 to turnthe other lighting systems ON. Based on exchanges of information betweenthe systems and/or the master controller, all the systems might turn OFFwhen all of the systems no longer detect occupancy for some period oftime. Of course, those skilled in the art will recognize that thecommunications between the intelligent lighting systems and/or with themaster controller may implement a variety of other occupancy relatedcontrol procedures.

The present teachings may utilize a variety of different fixtureconfigurations, e.g. using different arrangements of the opticalintegrating cavity and/or solid state emitters. Such differentconfigurations may also incorporate the detector(s) for sensing theother wavelengths in different ways. Hence, it may be helpful toconsider some alternative configurations in somewhat more detail.

In the examples discussed above relative to FIGS. 1A to 2, the LEDsources were coupled directly to openings at the points on the interiorof the cavity, to emit radiant energy directly into the interior of theoptical integrating cavity. It is also envisioned that the sources maybe somewhat separated from the cavity, in which case, the system mightinclude optical fibers or other forms of light guides coupled betweenthe sources and the optical integrating cavity, to supply radiant energyfrom the sources to the emission points into the interior of the cavity.FIG. 7 depicts such a system 50, which uses optical fibers.

The system 50 includes an optical integrating cavity 51, an aperture 53and a deflector with a reflective interior surface 55, similar to thosein earlier embodiments. At least a portion of the interior surface ofthe optical integrating cavity 51 is highly diffusely reflective,whereas the deflector surface 55 exhibits a specular reflectivity.Integration or combination of light by diffuse reflection within thecavity 51 produces a virtual source output of relatively uniformunpixelated light via the aperture 53. Typically, the distribution atthe aperture 53 is substantially Lambertian, and the integrationproduces a highly uniform light distribution across the aperture 53,which forms the virtual source output area of the cavity 51 and oftenforms all or a substantial part of the output area of the fixture.Typically, the unpixelated distribution of light across the aperture 53exhibits a maximum-to-minimum ratio of 2 to 1 (2:1) or less oversubstantially the entire optical output area.

The system 50 includes a control circuit 21 and power source 23, as inearlier embodiments. In the system 50, the radiant energy sourcescomprise LEDs 59 of three different wavelengths, e.g. to provide Red,Green and Blue light respectively. The sources may also include one ormore additional LEDs 61, either white or of a different color or for useas ‘sleepers,’ as discussed later. In this example (FIG. 7), the coverplate 63 of the cavity 51 has openings into which are fitted the lightemitting distal ends of optical fibers 65. The proximal light receivingends of the fibers 65 are coupled to receive light emitted by the LEDs59 (and 61 if provided). In this way, the LED sources 59, 61 may beseparate from the chamber 51, for example, to allow easier and moreeffective dissipation of heat from the LEDs. The fibers 65 transport thelight from the LED sources 59, 61 to the cavity 51. The cavity 51integrates the different colors of light from the LEDs as in the earlierexamples and supplies combined light out through the aperture 53. Thedeflector, in turn, directs the combined light to a desired field.Again, the intensity control by the circuit 21 adjusts the amount orintensity of the light of each type provided by the LED sources and thuscontrols the spectral characteristic of the combined light output.

The virtual source output light has a spectral characteristic, typicallyin the visible light region of the spectrum, produced by the diffuseprocessing and combination of visible light of the color or colorsproduced by the solid state light sources 59, 61. The system may includean additional emitter, to produce light of a different color orwavelength, as in several of the earlier examples; although in theexample of FIG. 7, an additional source is omitted for simplicity.Hence, the system will use passive detection, with regard toelectromagnetic energy of the other color or wavelength absent from thelight generated for illumination purposes. To that end, the system 50includes a detector 66, for sensing at least one wavelength ofelectromagnetic energy that is absent from the light produced by thesolid state light sources 59, 61 and/or absent from the combined lightproduced in the chamber 51 and output via the aperture 53 and deflector55.

In the example, the intent is for the detector 66 to sense acharacteristic of electromagnetic energy reflected within the cavity 51.The detector could be coupled directly to the cavity, as in several ofthe earlier examples. However, in this example, the system includesanother optical fiber 67 to couple electromagnetic energy from thecavity 51 to the detector 66.

The receiving end of the fiber 67 may be coupled to any convenient pointon a wall or within the volume of the optical integrating cavity 51. Inthis example (FIG. 7), the cover plate 63 of the cavity 51 has anadditional opening into which is fitted the light receiving end ofoptical fiber 67. The light emitting end of the fiber 67 is coupled tosupply the received light to the detector 66. In this way, the fiber 67transports the light from the cavity 51 to the detector 66.

Since the detector 66 senses a wavelength not present in the spectrum oflight generated in the cavity 51 by the sources 59, 61, the detector 66is responsive to energy of that wavelength that enters the cavity 51 viathe aperture 53 and reflects off the surface(s) of the cavity 51 and istransported through the fiber 67. In response, the detector 66 suppliesa detection signal to the control circuit 21, for processing in any ofthe various ways suggested above.

FIGS. 8 and 9 illustrate another example of a radiant energydistribution apparatus or system with sensing of at least one additionalwavelength to support system intelligence. FIG. 8 shows the overallsystem 30, including the fixture and the control circuitry; and thatdrawing shows the fixture is in cross-section. FIG. 9 is a bottom viewof the fixture. The system 30 is generally similar the system 10 of FIG.2. For example, the system 30 may utilize essentially the same type ofcontrol circuit 21 and power source 23, as in the earlier example.However, the shape of the optical integrating cavity and the deflectorare somewhat different.

The optical integrating cavity 31 has a diffusely reflective interiorsurface. In this example, the cavity 31 has a shape corresponding to asubstantial portion of a cylinder. In the cross-sectional view of FIG. 8(taken across the longitudinal axis of the cavity), the cavity 31appears to have an almost circular shape. Although a dome and curvedmember or plate could be used, in this example, the cavity 31 is formedby a substantially cylindrical element 33. At least the interior surfaceof the element 33 is highly diffusely reflective, so that the resultingoptical cavity 31 is highly diffusely reflective and functions as anintegrating cavity, with respect to the radiant energy spectrum producedby and processed in the system 30.

The optical integrating cavity 31 has an aperture 35 for allowingemission of combined radiant energy in the form of a virtual source. Inthis example, the aperture 35 is a rectangular passage through the wallof the cylindrical element 33. Because of the diffuse reflectivitywithin the cavity 31, light within the cavity is integrated beforepassage out of the aperture 35. As in the earlier examples, thecombination of light within the cavity 31 produces a relatively uniformintensity distribution across the output area formed by the aperture 35.Typically, the distribution is substantially Lambertian and theintegration produces a highly uniform light distribution across theaperture 17, which forms the virtual source output of the cavity 11 andoften forms all or a substantial part of the output area of the fixture.Typically, the unpixelated distribution of light across the aperture 17exhibits a maximum-to-minimum ratio of 2 to 1 (2:1) or less oversubstantially the entire optical output area.

The apparatus 30 also includes solid state sources of radiant energy ofdifferent wavelengths. In this example, the sources comprise LEDs 37,39. The LEDs are mounted in openings through the wall of the cylindricalelement 33, to essentially form two rows of LEDs on opposite sides ofthe aperture 35. The positions of these openings, and thus the positionsof the LEDs 37 and 39, typically are such that the LED outputs are notdirectly visible through the aperture 35. Hence, light from these LEDsreflects and diffuses within the cavity before emission through theoptical aperture, otherwise the locations are a matter of arbitrarychoice.

Thus, the LEDs 37 and 39 supply radiant energy into the interior of theoptical integrating cavity 31, through openings at points on theinterior surface of the optical integrating cavity not directly visiblethrough the aperture 35. A number of the LEDs emit radiant energy ofdifferent wavelengths. For example, arbitrary pairs of the LEDs 37, 39might emit four different colors of light, e.g. Red, Green and Blue asprimary colors and a fourth color chosen to provide an increasedvariability of the spectral characteristic of the integrated radiantenergy. One or more white light sources, e.g. white LEDs, also may beprovided.

Alternatively, a number of the LEDs may be initially active LEDs,whereas others are initially inactive sleeper LEDs. The sleeper LEDsoffer a redundant capacity that can be automatically activated on anas-needed basis. For example, the initially active LEDs might includetwo Red LEDs, two Green LEDs and a Blue LED; and the sleeper LEDs mightinclude one Red LED, one Green LED and one Blue LED.

The control circuit 21 controls the power provided to each of the LEDs37 and 39. The cavity 31 effectively combines the energy of differentwavelengths, from the various LEDs 37 and 39, so that the integratedradiant energy emitted through the aperture 35 includes the radiantenergy of all the various wavelengths. Control of the amount of lightemission of the sources, by the control circuit 21, sets a spectralcharacteristic of the combined radiant energy emitted through theaperture 35. If sleeper LEDs are provided, the control also activatesone or more dormant LEDs, on an “as-needed” basis, when extra output ofa particular wavelength or color is required.

The exemplary system 30 also includes a sensor or detector 40 fordetecting an amount (e.g. intensity) of electromagnetic energy of awavelength that is absent from the light produced by the LEDS 37, 39 andthe diffuse processing of the light from the LEDs within the cavity 31.In this example, the LEDs 37, 39 produce visible light, and the combinedlight produced by diffuse reflection of the light from the LEDs withinthe cavity 31 is visible light. It is intended that adjustment of theamounts of light from the LEDs 37, 39 will enable selection of thespectral characteristic of the visible light output of the system over asubstantial range of the visible light portion of the electromagneticspectrum. Hence, the detector 40 is of a type or configuration forsensing at least one wavelength outside of the visible light portion ofthe electromagnetic spectrum. Although the detector 40 might sense UVlight or other non-visible wavelengths, in the example of system 30, thedetector 40 senses IR light energy in the near IR range or in the far IRrange. The detector 40 supplies a sensing signal to the control circuit21, as in the earlier examples.

The color integrating energy distribution apparatus 30 may also includea deflector 41 having a specular reflective inner surface 43, toefficiently direct most of the light emerging from the aperture into arelatively narrow field of view. The deflector 41 expands outward from asmall end thereof coupled to the aperture 35. The deflector 41 has alarger opening 45 at a distal end thereof. The angle of the side wallsof the deflector and the shape of the distal opening 45 of the deflector41 define an angular field of radiant energy emission from the apparatus30 as well as the angular field of view for IR sensing purposes.

As noted above, the deflector 41 may have a variety of different shapes,depending on the particular lighting application. In the example, wherethe cavity 31 is substantially cylindrical, and the aperture isrectangular, the cross-section of the deflector 41 (viewed across thelongitudinal axis as in FIG. 8) typically appears conical, since thedeflector expands outward as it extends away from the aperture 35.However, when viewed on-end (bottom view —FIG. 9), the openings aresubstantially rectangular, although they may have somewhat roundedcorners. Alternatively, the deflector 41 may be somewhat oval in shape.The shapes of the cavity and the aperture may vary, for example, to haverounded ends, and the deflector may be contoured to match the aperture.

The deflector 41 comprises a reflective interior surface 43 between thedistal end and the proximal end. In several examples, at least asubstantial portion of the reflective interior surface 43 of the conicaldeflector exhibits specular reflectivity with respect to the combinedradiant energy, although different reflectivity may be provided, asnoted in the discussion of FIG. 2.

If redundancy is provided, “sleeper” LEDs would be activated only whenneeded to maintain the light output, color, color temperature, and/orthermal temperature. As discussed earlier with regard to the exemplarycontrol circuit of FIG. 3, the system 30 could have a color feedbacksensor coupled to provide feedback to the control circuit 21. Thefeedback sensor could be within the cavity or the deflector or at anoutside point illuminated by the integrated light from the fixture. AsLEDs age, they continue to operate, but at a reduced output level. Theuse of the sleeper LEDs greatly extends the lifecycle of the fixtures.Activating a sleeper (previously inactive) LED, for example, providescompensation for the decrease in output of the originally active LED.There is also more flexibility in the range of intensities that thefixtures may provide.

The system 30 also includes a source 47 of IR light, that is to say ofat least one wavelength absent from the light produced by the LEDs 37,39 and the combined light output emitted through the aperture 35. Thesource 47 may emit light of a different wavelength from that sensed bythe detector 40, but in this example, the IR source 47 emits light of awavelength that the detector 40 will sense. The IR source 47 may bemounted on or near the fixture but outside the deflector 41 as shown, orthe IR source 47 may be mounted at a different location. IR light fromthe source 47 illuminates at least a portion of a region intended to beilluminated by the combined light output from the aperture 35.

The reflected IR light, e.g. from a person that enters the region,enters the cavity 31 via the deflector 41 and the aperture 35. The IRlight reflects and diffuses within the cavity 31, and at least some ofthat light impacts on the detector 40. Upon receiving the IR light viathe cavity 31, the detector 40 generates a responsive sensing signal andsupplies that signal to the control circuit 21 for further processing.In this way, the detector 40 and the source 47 provide a detectioninput, for example, for use in occupancy detection as discussed aboverelative to FIG. 4, although the source and detector could be used inother ways as also suggested earlier.

In the examples above, a deflector was used to provide further opticalprocessing of the integrated light emerging from the aperture of thefixture, and in some cases for processing detectable electromagneticenergy before entry into the chamber and sensing by the detector. Avariety of other optical processing devices may be used in place of orin combination with a deflector or other optical processing element(s).Examples include various types of diffusers, collimators, variable focusmechanisms, and iris or aperture size control mechanisms. Several ofthese examples are shown in FIGS. 10A to 10C.

FIGS. 10A to 10C are cross-sectional views of several examples ofoptical cavity LED fixtures using various forms of secondary opticalprocessing elements to process the integrated energy emitted through theaperture. Although similar fixtures may process and emit other radiantenergy spectra, for discussion here we will assume these “lighting”fixtures process and emit light in the visible part of the spectrum.These first three examples are similar to each other, and the commonaspects are described first. Each fixture 250 (250 a to 250 c in FIGS.10A to 10C, respectively) includes an optical integrating cavity 11 andLEDs 19 similar to those in the example of FIG. 2 and like referencenumerals are used to identify the corresponding components. Integrationor combination of light by diffuse reflection within the cavity 11produces a relatively uniform unpixelated virtual source output via theaperture 17. Typically, the distribution at the aperture 17 issubstantially Lambertian, and the integration produces a highly uniformlight distribution across the aperture, which forms the output area ofthe cavity and often forms all or a substantial part of the output areaof the fixture. Typically, the unpixelated distribution of light acrossthe aperture 17 exhibits a maximum-to-minimum ratio of 2 to 1 (2:1) orless over substantially the entire optical output area. Each fixturealso includes a detector 18, in this instance for detection of IRenergy, and each system includes at least two IR sources, shown attachedto or in close proximity to the portion of the fixture forming thecavity. A power source and control circuit similar to those used in theearlier example of FIG. 2 provide the drive currents for the LEDs, andin view of the similarity, the power source and control circuit areomitted from these figures, to simplify the illustrations.

In the examples of FIGS. 10A to 10C, each light fixture 250 a to 250 cincludes an optical integrating cavity 11, formed by a dome 11 and acover plate 15. The surfaces of the dome 13 and cover 15 forming theinterior surface(s) of the cavity 11 are diffusely reflective. One ormore apertures 17, in these examples formed through the plate 15,provide a light passage for transmission of reflected and integratedlight outward from the cavity 11. Materials, positions, orientations andpossible shapes for the elements 11 to 17 and the resulting combined andunpixelated light provided at the aperture 17 have been discussed above.

As in the earlier examples, each fixture 250 a to 250 c includes anumber of LEDs 19 emitting light of different wavelengths into thecavity 11, as in the example of FIG. 2. A number of the LEDs will beactive, from initial start-up, whereas others may initially be inactive‘sleepers,’ as also discussed above. The possible combinations andpositions of the LEDs 19 have been discussed in detail above, inrelation to the earlier examples. Again, the LEDs 19 emit light ofmultiple colors into the interior of the optical integrating cavity.Control of the amplitudes of the drive currents applied to the LEDs 19controls the amount of each light color supplied into the cavity 11. Thecavity 11 integrates the various amounts of light of the differentcolors into a combined light for emission through the aperture 17.

The LEDs 19 produce visible light, and the combination by processing ofthe light from the LEDs by reflection within the cavity 11 produces acombined light in the visible portion of the spectrum. In each of theseexamples, each of the systems 250 a to 250 c includes a detector 18 fordetecting at least one wavelength of electromagnetic energy that isabsent from the light generated by the LEDs 19 and/or by the combinationof such light within the cavity 11. Although the wavelength detectedcould be in the visible portion or the UV portion of the spectrum, inthe examples of FIGS. 10A to 10C, the detector 18 is an IR detector.

Each of the systems 250 a to 250 c includes at least one source foremitting electromagnetic energy of at least one wavelength that isabsent from the light generated by the LEDs 19 and/or by the combinationof such light within the cavity 11. The detector 18 is coupled toreceive IR light from within the cavity 11. In these examples, theadditional sources take the form of IR emitting LEDs 24 that aremounted/coupled so as to emit IR light outside the cavity 11, that is tosay to illuminate an area with the IR light without first passing the IRlight from the sources 24 through the cavity 11 and the aperture 17. TheIR light from the sources 24 may emit IR light of the same wavelength assensed by the detector 18, for example, for occupancy detectionapplications or the like. It also possible that the sources 24 will emitIR light of a different wavelength, e.g. in the near or far IR rangewhereas the detector 18 detects far or near IR light respectively.Control of the operation of the IR sources 24 and processing of thesensing signal from the detector 18 typically are the same as discussedabove with regard to the examples of FIG. 2 and FIG. 3.

The three examples (FIGS. 10A to 10C) differ as to the processingelement coupled to the aperture that processes the integrated colorlight output coming out of the optical aperture 17. Of course, IR lightcoming to the fixture to enter the cavity 11 through the aperture 17will also pass through the respective processing element. In the exampleof FIG. 10A, instead of a deflector as in FIG. 2, the fixture 250 aincludes a lens 251 a in or covering the opening forming thetransmissive optical aperture 17. The lens may take any convenient form,for focusing or diffusing the emitted combined light, and/or diffusingor focusing the incoming IR light, as desired for a particularapplication of the fixture 250 a. The lens 251 a may be clear ortranslucent.

In the example of FIG. 10B, the fixture 250 b includes a curvedtransmissive diffuser 251 a covering the aperture 17. The diffuser maytake any convenient form, for example, a white or clear dome of plasticor glass. Alternatively, the diffuser 251 b may be formed of a prismaticmaterial. In addition to covering the aperture, the element 251 bdiffuses the emitted combined light, as desired for a particularapplication of the fixture 250 b. The dome shaped diffuser may coverjust the aperture 17, as shown at 251 b, or it may cover the backs ofthe LEDs 19 as well. Of course, the dome shaped diffuser 251 b will alsoprocess incoming light, such as the IR light entering the cavity fordetection by the detector 18.

In the example of FIG. 10C, a holographic diffraction plate or grading251 c serves as the optical output processing element in the fixture 250c. The holographic grating is another form of diffuser. The holographicdiffuser 251 c is located in the opening forming optical aperture 17 orattached to the plate 15 to cover the aperture 17. A holographicdiffuser provides more precise control over the diffuse area ofillumination and increases transmission efficiency. Holographicdiffusers and/or holographic films are available from a number ofmanufacturers, including Edmund Industrial Optics of Barrington, N.J. Ofcourse, the holographic diffuser 251 c will also process incoming light,such as the IR light entering the cavity for detection by the detector18.

Those skilled in the art will recognize that still other lightprocessing elements may be used in place of the output lens 251 a, thediffuser 251 b and the holographic diffuser 251 c, to process or guidethe integrated light output. For example, a fiber optic bundle may beused to channel the output light to a desired point, for examplerepresenting a pixel on a large display screen (e.g. a jumbotron). Sucha further processing element would also process incoming light, beforeentry into the cavity for reflection and detection.

To provide a uniform output distribution from the apparatus, it is alsopossible to construct the optical cavity so as to provide constructiveocclusion. Constructive Occlusion type transducer systems utilize anelectrical/optical transducer optically coupled to an active area of thesystem, typically the aperture of a cavity or an effective apertureformed by a reflection of the cavity. The systems utilize diffuselyreflective surfaces, such that the active area exhibits a substantiallyLambertian characteristic. A mask occludes a portion of the active areaof the system, in the examples, the aperture of the cavity or theeffective aperture formed by the cavity reflection, in such a manner asto achieve a desired response or output performance characteristic forthe system. In examples of the present systems using constructiveocclusion, the optical integrating cavity comprises a base, a mask and acavity in either the base or the mask. The mask would have a diffuselyreflective surface facing toward the aperture. The mask is sized andpositioned relative to the active area so as to constructively occludethe active area. As with the earlier optics, constructive occlusionapplies to both outgoing and incoming light. Hence, constructiveocclusion also tailors sensitivity of the detection function. It may behelpful to consider some examples using constructive occlusion.

FIGS. 11 and 12 depict a first, simple embodiment of a light distributorapparatus or system 70, for projecting integrated multi-wavelength lightwith a tailored intensity distribution, using the principles ofconstructive occlusion. In the cross-section illustration, the system 70is oriented to provide downward illumination. Such a system might bemounted in or suspended from a ceiling or canopy or the like. Thoseskilled in the art will recognize that the designer may choose to orientthe system 70 in different directions, to adapt the system to otherlighting applications.

The lighting system 70 includes a base 73, having or forming a cavity75, and adjacent shoulders 77 and 79, constructed in a manner similar tothe elements forming integrating cavities in the earlier examples. Inparticular, the interior of the cavity 75 is diffusely reflective, andthe down-facing surfaces of shoulders 77 and 79 may be reflective. Ifthe shoulder surfaces are reflective, they may be specular or diffuselyreflective. A mask 81 is disposed between the cavity aperture 85 and thefield to be illuminated. In this symmetrical embodiment, the interiorwall of a half-cylindrical base 73 forms the cavity 75; therefore theaperture 85 is rectangular. The shoulders 77 formed along the sides ofthe aperture 85 are rectangular. If the base were circular, with ahemispherical cavity, the shoulders typically would form a ring that maypartially or completely surround the aperture.

In many constructive occlusion embodiments, the cavity 75 comprises asubstantial segment of a sphere. For example, the cavity may besubstantially hemispherical, as in earlier examples. However, thecavity's shape is not of critical importance. A variety of other shapesmay be used. In the illustrated example, the half-cylindrical cavity 75has a rectangular aperture, and if extended longitudinally, therectangular aperture may approach a nearly linear aperture (slit).Practically any cavity shape is effective, so long as it has a diffusereflective inner surface. A hemisphere or the illustrated half-cylindershape is preferred for the ease in modeling for the light output towardthe field of intended illumination and the attendant ease ofmanufacture. Also, sharp corners tend to trap some reflected energy andreduce output efficiency.

For purposes of constructive occlusion, the base 73 may be considered tohave an active optical area, preferably exhibiting a substantiallyLambertian energy distribution. Where the cavity is formed in the base,for example, the planar aperture 85 formed by the rim or perimeter ofthe cavity 75 forms the active surface with substantially Lambertiandistribution of energy emerging through the aperture 85. As shown in alater embodiment, the cavity 75 may be formed in the facing surface ofthe mask. In such a system, the surface of the base may be a diffuselyreflective surface, therefore the active area on the base wouldessentially be the mirror image of the cavity aperture on the basesurface, that is to say the area reflecting energy emerging from thephysical aperture of the cavity in the mask.

The mask 81 constructively occludes a portion of the optically activearea of the base with respect to the field of intended illumination. Inthe example of FIG. 11, the optically active area is the aperture 85 ofthe cavity 75; therefore the mask 81 occludes a substantial portion ofthe aperture 85, including the portion of the aperture on and about theaxis of the mask and cavity system. The surface of the mask 81 facingtowards the aperture 85 is reflective. Although it may be specular,typically this surface is diffusely reflective.

The relative dimensions of the mask 81 and aperture 85, for example therelative widths (or diameters or radii in a more circular system) aswell as the separation distance of the mask 81 away from the aperture85, control the constructive occlusion performance characteristics ofthe lighting system 70. Certain combinations of these parameters producea relatively uniform emission intensity with respect to angles ofemission, over a wide portion of the field of view about the system axis(vertically downward in FIG. 11), covered principally by theconstructive occlusion. Other combinations of size and separationdistance result in a system performance that is uniform with respect toa wide planar surface perpendicular to the system axis at a fixeddistance from the active area.

The shoulders 77, 79 also are reflective and therefore deflect at leastsome light downward. The shoulders (and side surfaces of the mask)provide additional optical processing of combined light from the cavity.The angles of the shoulders and the reflectivity of the surfaces thereoffacing toward the region to be illuminated by constructive occlusionalso contribute to the intensity distribution over that region. In theillustrated example, the reflective shoulders are horizontal, althoughthey may be angled somewhat downward from the plane of the aperture.

With respect to the energy from the solid state light emitting elements(e.g. LEDs 87), the interior space formed between the cavity 75 and thefacing surface of the mask 81 operates as an optical integrating cavity,in essentially the same manner as the integrating cavities in theprevious embodiments. The LEDs could provide light of one color, e.g.white. In the example, the LEDs 87 provide light of a number ofdifferent colors, and thus of different wavelengths. The optical cavitycombines the light of multiple colors supplied from the LEDs 87. Thecontrol circuit 21 controls the amount of each color of light suppliedto the chamber and thus the proportion thereof included in the combinedoutput light. The constructive occlusion serves to distribute that lightin a desired manner over a field or area that the system 70 is intendedto illuminate, with a tailored intensity distribution.

The LEDs 87 could be located at (or coupled by optical fiber to emitlight) from any location or part of the surface of the cavity 75.Preferably, the LED outputs are not directly visible through theun-occluded portions of the aperture 85 (between the mask and the edgeof the cavity). The LED outputs diffusely reflect one or more timesbefore combined light emission through the gap between the rim of thecavity (aperture edge) and the perimeter of the mask. In examples of thetype shown in FIGS. 11 and 12, the easiest way to so position the LEDoutputs is to mount the LEDs 87 (or provide fibers or the like) so as tosupply light to the chamber through openings through the mask 81.

FIG. 12 also provides an example of an arrangement of the LEDs in whichthere are both active and inactive (sleeper) LEDs of the various colors.As shown, the active part of the array of LEDs 87 includes two Red LEDs(R), one Green LED (G) and one Blue LED (B). The initially inactive partof the array of LEDs 87 includes two Red sleeper LEDs (RS), one Greensleeper LED (GS) and one Blue sleeper LED (BS). If other wavelengths orwhite light sources are desired, the apparatus may include an active LEDof the other color (O) as well as a sleeper LED of the other color (OS).The precise number, type, arrangement and mounting technique of the LEDsand the associated ports through the mask 81 are not critical. Thenumber of LEDs, for example, is chosen to provide a desired level ofoutput energy (intensity), for a given application.

The system 70 includes a control circuit 21 and power source 23. Theseelements control the operation and output intensity of each LED 87. Theindividual intensities determine the amount of each color light includedin the integrated and distributed output. The control circuit 21functions in essentially the same manner as in the other examples.

The constructive occlusion provides a tailored intensity distributionwith respect to light generated by the LEDs 87, diffusely reflectedwithin the optical integrating cavity 75 and emitted around the gapbetween the aperture 85 and the edge of the mask 81. Reflective surfacesof the shoulders 77, 79 and of the mask also tend to distribute thatcombined/processed light output over the area or region to beilluminated by the system 70. The optical processing by these elements,however, also applies to incoming light from that region, for example,as might be sensed by a detector 88 coupled to the cavity 75. Althoughthe detector may be coupled to receive reflected light from other pointsin or on the wall of the cavity, in the example, the detector 88 islocated or otherwise coupled to receive light at a point on the mask 81.As in the earlier examples, the detector 88 is configured or of a typethat detects a wavelength of electromagnetic energy that is absent fromthe light generated by the LEDs and/or by the processing of the lightfrom the LEDs by the cavity and mask. The detector 88 provides a sensingsignal to the control circuit 21, as discussed above.

The system 70 also includes a source 89 of electromagnetic energy of atleast one wavelength that is absent from the light generated by the LEDs87 and/or by the processing of the light from the LEDs by the cavity andmask. In this example, the source emits light outside the cavity andmask system. The control 21 controls operation of the source 89, in amanner similar to several of the earlier examples.

As noted, the optical processing in the fixture in the system 70operates in both directions, to process light being emitted by thesystem (generated by the LEDs 87) and to process electromagnetic energyreceived by the system (for reception/sensing by the detector 88). Inthe outgoing direction, a substantially Lambertian emitting surface LScan be created using the point illuminating type LED elements 87 thatilluminate the cavity 75 whose interior surface is diffusely reflective.The cavity 87 diffusely reflects light from the point sources such thata uniformly illuminated surface is created at the aperture 85 of thecavity 75. Correspondingly, a substantially Lambertian detection surfaceLS can be created using a point detecting element such as a photodiodeor the light used for the detector 88, which detects light within thecavity 75. The cavity 75 diffusely reflects electromagnetic energyentering the cavity 75 through the aperture 85 such that the pointdetecting type detector element 88 detects electromagnetic energyuniformly with respect to the aperture 85.

The occlusion provided by the mask 81 tailors the sensitivitydistribution of the system in much the same way that it tailors theoutput distribution of the system. Properly sized and positioned fromthe area of aperture 85, the mask 81 selectively blocks or occludesportions of the aperture area with respect to incoming light. Theocclusion by the mask tends to reduce the dependency or sensitivity ofthe detection function to the angle of the incoming light. Thereflective surfaces of the shoulders 77 and 79 and of the mask 81 mayalso help to direct incoming light through the aperture and thus furthertailor the sensitivity of the system to detect incoming light. Theemission and detection profiles can be substantially uniform for mostangles, in accordance with the selected mask/cavity/aperture geometry.With the use of shoulder, the uniformity of emission distribution anduniformity of sensitivity to incoming light may extend out near thehorizon of the fixture.

Hence, the combined light output of the system 70 is relativelyuniformly distributed by operation of the mask and cavity typeconstructive occlusion. The incoming light, of the wavelength(s) towhich the detector 88 is sensitive, is also processed by the opticalelements of the system 70 so that the detection profile is relativelyuniform over a wide range of angles of incidence of the incoming light.

FIGS. 13 and 14 illustrate a second mask and cavity type constructiveocclusion example. In this example, the physical cavity is actuallyformed in the mask, and the active area of the base is a flat reflectivepanel of the base.

The illustrated system 90 comprises a flat base panel 91, a mask 93, LEDlight sources 95, a detector 96 and a conical deflector 97. The systemmay also include a source 98. The detector 96 and source 98 are fordetection and emission respectively of light or other electromagneticenergy of one or more wavelengths absent from the light emissions by theLEDs 95 for the illumination application, as in earlier examples.

The system 90 is circularly symmetrical about a vertical axis, althoughit could be rectangular or have other shapes. The base 91 includes aflat central region 99 between the walls of the deflector 97. The region99 is reflective and forms or contains the active optical area on thebase facing toward the region or area to be illuminated by the system90.

The mask 93 is positioned between the base 91 and the region to beilluminated by constructive occlusion. For example, in the orientationshown, the mask 93 is above the active optical area 99 of the base 91,for example to direct light toward a ceiling for indirect illumination.Of course, the mask and cavity system could be inverted to serve as adownlight for task lighting applications, or the mask and cavity systemcould be oriented to emit light in directions appropriate for otherapplications.

In this example, the mask 93 contains the diffusely reflective cavity101, constructed in a manner similar to the integrating cavities in theearlier examples. The physical aperture 103 of the cavity 101 and of anydiffusely reflective surface(s) of the mask 93 that may surround thataperture form an active optical area on the mask 93. Such an active areaon the mask faces away from the region to be illuminated and toward theactive surface 99 on the base 91. The surface 99 is reflective,preferably with a diffuse characteristic. The surface 99 of the base 91essentially acts to produce a diffused mirror image of the mask 93 withits cavity 101 as projected onto the base area 99. The reflection formedby the active area of the base becomes the effective aperture of theoptical integrating cavity (between the mask and base) when the fixtureis considered from the perspective of the area of intended illumination.

With respect to light emissions, the surface area 99 reflects energyemerging from the aperture 103 of the cavity 101 in the mask 93. Themask 93 in turn constructively occludes light diffused from the activebase surface 99 with respect to the region illuminated by the system 90.The dimensions and relative positions of the mask and active region onthe base control the light distribution performance of the system, inessentially the same manner as in the mask and cavity system of FIGS. 11and 12.

With respect to incoming light, e.g. of the wavelength detectable by thedetector 96, the mask 93 constructively occludes light diffused from theactive base surface 99 with respect to the region illuminated by thesystem 90. The surface area 99 reflects energy entering the system(after occlusion by the mask) toward the aperture 103 of the cavity 101in the mask 93. The dimensions and relative positions of the mask andactive region on the base control the light sensitivity performance ofthe system, in essentially the same manner as in the mask and cavitysystem of FIGS. 11 and 12.

The system 90 includes a control circuit 21 and associated power source23, for supplying controlled electrical power to the LED type solidstate sources 95. In this example, the LEDs emit light through openingsthrough the base 91, preferably at points not directly visible fromoutside the system. LEDs of the same type, emitting the same color oflight, could be used. However, in the example, the LEDs 95 supplyvarious wavelengths of light, and the circuit 21 controls the power ofeach LED, to control the amount of each color of light in the combinedoutput, as discussed above relative to the other examples.

The base 91 could have a flat ring-shaped shoulder with a reflectivesurface. In this example, however, the shoulder is angled toward thedesired field of illumination to form a conical deflector 97. The innersurface of the deflector 97 is reflective, as in the earlier examples.

The deflector 97 has the shape of a truncated cone, in this example,with a circular lateral cross section. The cone has two circularopenings. The cone tapers from the large end opening to the narrow endopening, which is coupled to the active area 99 of the base 91. Thenarrow end of the deflector cone receives light from the surface 99 andthus from diffuse reflections between the base and the mask.

The entire area of the inner surface of the cone 97 is reflective. Atleast a portion of the reflective surface is specular, as in thedeflectors of the earlier examples. The angle of the wall(s) of theconical deflector 97 substantially corresponds to the angle of thedesired field of view of the illumination intended for the system 90.Because of the reflectivity of the wall of the cone 97, most if not allof the light reflected by the inner surface thereof would at leastachieve an angle that keeps the light within the field of view.

In the illustrated example, the LED light sources 95 emit multiplewavelengths of light into the mask cavity 101. The light sources 95 maydirect some light toward the inner surface of the deflector 97. Lightrays impacting on the diffusely reflective surfaces, particularly thoseon the inner surface of the cavity 101 and the facing surface 99 of thebase 91, reflect and diffuse one or more times within the confines ofthe system and emerge through the gap between the perimeter of theactive area 99 of the base and the outer edge of the mask 93. The maskcavity 101 and the base surface 99 function as an optical integratingcavity with respect to the light of various wavelengths, and the gapbecomes the actual integrating cavity aperture from which substantiallyuniform combined light emerges. The light emitted through the gap and/orreflected from the surface of the inner surface of the deflector 97irradiates a region (upward in the illustrated orientation) with adesired intensity distribution and with a desired spectralcharacteristic, essentially as in the earlier examples.

FIGS. 15A and 15B illustrate yet another mask and cavity typeconstructive occlusion example. This example is generally similar tothat of FIGS. 11 and 12 except that the mask and cavity fixture 160 iscircular. Other system elements, such as the power source and controlcircuit are omitted, as they will generally be the same as in theexamples discussed above.

The fixture 160 of the light system includes a base 163, having orforming a cavity 165, and an adjacent shoulder 167, which in thisexample encircles the aperture 175 of the cavity 165. The base, cavityand shoulder may be constructed in a manner similar to the elements inthe earlier examples. The interior of the cavity 165 is diffuselyreflective, and the upward-facing surface of the shoulder 167 may bereflective. A mask 171 is disposed between the cavity aperture 175 andthe field to be illuminated. Although other shapes may be used, theexemplary cavity 165 consists of a segment of a sphere, for exampleapproximately a hemisphere.

For purposes of constructive occlusion, the base 163 may be consideredto have an active optical area, preferably exhibiting a substantiallyLambertian energy distribution. Where the cavity is formed in the base,for example, the planar aperture 175 formed by the rim or perimeter ofthe cavity 165 forms the active surface with substantially Lambertiandistribution of energy emerging through the aperture. The mask 171constructively occludes a portion of the optically active area of thebase, that is to say the aperture 175 in this example, with respect tothe field of intended illumination. The surface of the mask 171 facingtowards the aperture 175 is reflective. Although it may be specular,typically this surface is diffusely reflective.

The mask 171 also serves as a board or support on which are mounted anumber of solid state emitters, typically LEDs, 177. The LED typeemitters 177 serve as point sources for emission of visible light energyinto the cavity 165 for diffuse processing by the mask and cavitysystem. The mask 171 also serves as a board or support on which aremounted a number of solid state light detectors 178. The solid statelight detectors 178 serve as point sensors for sensing one or morewavelengths of electromagnetic energy that are absent from the LEDemissions and/or from the combined light generated by processing of theLED emissions by the mask and cavity system.

The relative dimensions of the mask 171 and aperture 175, for examplethe relative widths (or diameters or radii in a more circular system) aswell as the separation distance of the mask 171 away from the aperture175, control the constructive occlusion performance characteristics ofthe light fixture 160, both with respect to light emitted from the lightfixture 160 and with respect to light received and detected within thefixture 160. Certain combinations of these parameters produce arelatively uniform emission intensity with respect to angles ofemission, over a wide portion of the field of emission about the systemaxis (vertically upward in FIG. 15A), covered principally by theconstructive occlusion. Those combinations of fixture parameterssimilarly produce a relatively uniform sensitivity to incoming lightwith respect to angles of incidence over a wide portion of the field ofview about the system axis (vertically upward in FIG. 15A), coveredprincipally by the constructive occlusion. Other combinations of sizeand height result in a system performance (emission and detection) thatis uniform with respect to a wide planar surface perpendicular to thesystem axis at a fixed distance from the active area.

FIGS. 16A to 16D illustrate yet another mask and cavity typeconstructive occlusion example. This example uses one mask and cavityarrangement for emissions of illuminating light in the visible portionof the spectrum as well as for electromagnetic energy of anotherwavelength, but it uses a second mask and cavity arrangement for thedetection function. The system implements nested constructive occlusionin that the cavity for the detector is actually formed in the mask thatoccludes the emission aperture. FIG. 16A a top plan view of the lightfixture 180, FIG. 16B is a cross-sectional view of the fixture 180 ofFIG. 16A taken along line B-B; FIG. 16C is a cross-sectional view of thefixture taken along line C-C of FIG. 16B; and FIG. 16D is across-sectional view of the fixture taken along line D-D of FIG. 16B.

1) The fixture 180 of the light system includes a first base 181, havingor forming a first cavity 182. The rim of the cavity 182 forms a firstaperture 183. The base 181 also has a shoulder 184, which in thisexample encircles the aperture 183 of the cavity 182. The first base,first cavity and shoulder may be constructed in a manner similar to theelements in the earlier examples. The interior of the cavity 182 isdiffusely reflective, and the upward-facing surface of the shoulder 184may be reflective. Although other shapes may be used, the exemplarycavity 182 consists of a segment of a sphere, for example approximatelya hemisphere.2) A first mask 185 is disposed between the cavity aperture 183 and thefield to be illuminated. The aperture 183 forms a substantiallyLambertian energy distribution area. The mask 185 constructivelyoccludes a portion of Lambertian virtual source formed at the aperture183, with respect to the field of intended illumination. The surface ofthe mask 185 facing towards the aperture 183 is reflective. Although itmay be specular, typically this surface is diffusely reflective.

The first mask 185 also serves as a board or support on which aremounted a number of solid state emitters, typically LEDs. In thisexample, there are two types of LEDs. One or more first LEDs 186 serveas point sources for emission of visible light energy into the cavity182 for diffuse processing by the first mask and cavity system. Thesystem 180 also includes one or more LEDs 187 for emittingelectromagnetic energy of a wavelength that is absent from the lightgenerated by the LEDs 186. Typically, if the LEDs 186 generate visiblelight, the LED 187 will emit light outside the visible range of thespectrum. Although the LED 187 could emit UV light, for purposes of thisdiscussion, the LED 187 emits IR light. The LEDs 186 and 187 are visibleon the cavity facing surface of the first mask 185 in thecross-sectional view of FIG. 16C.

The relative dimensions of the first mask 185 and aperture 183, forexample the relative widths (or diameters or radii in a more circularsystem) as well as the separation distance of the first mask 185 awayfrom the aperture 183, control the constructive occlusion performancecharacteristics of light emissions from the fixture 180. Certaincombinations of these parameters produce a relatively uniform emissionintensity with respect to angles of emission, over a wide portion of thefield of emission about the system axis (vertically upward in FIG. 15B),covered principally by the constructive occlusion. Other combinations ofsize and height result in a system emission performance that is uniformwith respect to a wide planar surface perpendicular to the system axisat a fixed distance from the aperture.

As outlined above, the first mask 185 constructively occludes the firstaperture 183, so as to tailor the distribution performance of thesystem, that is to say the distribution of light and otherelectromagnetic energy from the LEDs 186 and 187. However, in thisexample, the first mask 185 also is the base (second base) with respectto the detector function. For detection purposes, the element 185 has orforms a second cavity 192. The rim of the cavity 192 forms a secondaperture 193. The mask/base 185 also has a second shoulder 194, which inthis example encircles the aperture 193 of the cavity 192. The mask/base185, second cavity 192 and shoulder 194 may be constructed in a mannersimilar to the elements in the earlier examples. The interior of thecavity 192 is diffusely reflective, and the upward-facing surface of theshoulder 194 may be reflective. Although other shapes may be used, theexemplary cavity 192 consists of a segment of a sphere, for exampleapproximately a hemisphere.

A second mask 195 is disposed between the cavity aperture 193 and thefield to be illuminated. The aperture 193 forms a substantiallyLambertian energy reception area for the detection function. The mask195 constructively occludes a portion of the aperture 193 with respectto the field of intended illumination and thus with respect to the areafrom which energy is also to be detected. The surface of the mask 195facing towards the aperture 193 is reflective. Although it may bespecular, typically this surface is diffusely reflective.

The second mask 195 also serves as a board or support on which ismounted at least one solid state detector 197. The solid state lightdetector 197 serves as a point sensor for sensing one or morewavelengths of electromagnetic energy that is absent from the emissionsof LEDs 186 and/or from the combined light generated by processing ofthose LED emissions by the first mask and cavity system 182 and 185.

Since the LEDs 186 emit visible light, the detector 197 will typicallydetect electromagnetic energy outside the visible portion of thespectrum, such as UV light. In this example, the detector 197 detects IRlight. For some applications, such as two way data communications, theIR detector 197 would detect IR energy of a different wavelength than isemitted by the IR LED 187. However, for an occupancy sensing applicationor the like, the IR detector 197 might detect IR energy of the samewavelength that is emitted by the IR LED 187, e.g. so that the detector187 is sensitive to reflections of IR initially generated by the IR LED187.

The relative dimensions of the second mask 195 and aperture 193, forexample the relative widths (or diameters or radii in a more circularsystem) as well as the separation distance of the mask 195 away from theaperture 193, control the constructive occlusion performancecharacteristics of light detection by the fixture 180. Certaincombinations of these parameters produce a relatively uniformsensitivity with respect to angles of incidence of incoming IR light,over a wide portion of the field of view about the system axis(vertically upward in FIG. 15B), covered principally by the constructiveocclusion of the second mask and cavity arrangement. Other combinationsof size and height result in a system detection performance that isuniform with respect to a wide planar surface perpendicular to thesystem axis at a fixed distance from the active area at the aperture193. The tailored sensitivity of the detection function may be similarto the tailored light distribution, or the two mask and cavity systemsmay be configured to produce different performance profiles.

Although not shown in these drawings, the detector 197 would provide adetection signal to the system control circuit, as in the earlierexamples. The control circuit in turn would process and respond to thatsignal in one or more of the ways discussed above, for example tocontrol the outputs of the visible light LEDs 186 based on occupancystatus as indicated by the reflected IR level indicated by the sensingsignal from the detector 197.

In the example of FIGS. 16A to 16D discussed so far, the elements 187were IR LEDs and the element 197 was an IR detector. Of course theselocations/roles may be reversed. The system would work with the element197 constructed as an IR emitter and one or more elements 187constructed as an IR detector.

Additional information regarding constructive occlusion based systemsfor generating and distributing radiant energy and/or for receiving anddetecting radiant energy may be found in commonly assigned U.S. Pat.Nos. 6,342,695, 6,334,700, 6,286,979, 6,266,136 and 6,238,077. The colorintegration and sensing/control principles discussed herein may beadapted to any of the constructive occlusion devices discussed in thosepatents.

The exemplary systems discussed herein may have any size desirable forany particular application. A system may be relatively large, forlighting a room or providing spot or flood lighting. The system also maybe relatively small, for example, to provide a small pinpoint of light,for an indicator or the like. The system 250 a, with or even without thelens, is particularly amenable to miniaturization. For example, insteadof a plate to support the LEDs, the LEDs could be manufactured on asingle chip. If it was not convenient to provide the aperture throughthe chip, the aperture could be formed through the reflective dome.

As shown by the discussion above, each of the various radiant energyemission systems with solid state light sources and an optical cavity tocombine the energy from the sources provides a highly effective means tocontrol the color produced by one or more fixtures. The outputcharacteristics are controlled simply by controlling the amount of lightfrom each of the sources supplying radiant energy to the chamber.

Settings for a desirable color are easily reused or transferred from onesystem/fixture to another. If color/temperature/balance offered byparticular settings are found desirable, e.g. to light a particularproduct on display or to illuminate a particular person in a studio ortheater, it is a simple matter to record those settings and apply themat a later time. Similarly, such settings may be readily applied toanother system or fixture, e.g. if the product is displayed at anotherlocation or if the person is appearing in a different studio or theater.It may be helpful to consider the product and person lighting examplesin somewhat more detail.

For the product, assume that a company will offer a new soft drink in acan having a substantial amount of red product markings. The company cantest the product under lighting using one or more fixtures as describedherein, to determine the optimum color to achieve a desired brilliantdisplay. In a typical case, the light will generally be white to theobserver. In the case of the red product container, the white light willhave a relatively high level of red, to make the red markings seem toglow when the product is viewed by the casual observer/customer. Whenthe company determines the appropriate settings for the new product, itcan distribute those settings to the stores that will display and sellthe product. The stores will use other fixtures of any type disclosedherein. The fixtures in the stores need not be of the exact same typethat the company used during product testing. Each store uses thesettings received from the company to establish the spectralcharacteristic(s) of the lighting applied to the product by the store'sfixture(s), in our example, so that each product display provides thedesired brilliant red illumination of the company's new soft drinkproduct.

Consider now a studio lighting example for an actor or newscaster. Theperson is tested under lighting using one or more fixtures as describedherein, to determine the optimum color to achieve desired appearance invideo or film photography of the individual. Again, the light willgenerally be white to the observer, but each person will appear betterat somewhat different temperature or color balance levels. One personmight appear more healthy and natural under warmer light, whereasanother might appear better under bluer/colder white light. Aftertesting to determine the person's best light color settings, thesettings are recorded. Each time the person appears under any lightingusing the systems disclosed herein, in the same or a different studio,the technicians operating the lights can use the same settings tocontrol the lighting and light the person with light of exactly the samespectral characteristic(s). Similar processes may be used to define aplurality of desirable lighting conditions for the actor or newscaster,for example, for illumination for different moods or different purposesof the individual's performances.

The methods for defining and transferring set conditions, e.g. forproduct lighting or personal lighting, can utilize manual recordings ofsettings and input of the settings to the different lighting systems.However, it is preferred to utilize digital control, in systems such asdescribed above relative to FIG. 3. Once input to a given lightingsystem, a particular set of parameters for a product or individualbecome another ‘preset’ lighting recipe stored in digital memory, whichcan be quickly and easily recalled and used each time that theparticular product or person is to be illuminated.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that they may be appliedin numerous applications, only some of which have been described herein.It is intended by the following claims to claim any and allmodifications and variations that fall within the true scope of thepresent concepts.

1-41. (canceled)
 42. A lighting system for humanly visible lightillumination, comprising: a light fixture, comprising: (a) a pluralityof light emitting diodes (LEDs) for generating visible light; (b) achamber having a reflective interior surface, at least a portion of theinterior surface having a diffuse reflectivity such that the chambercombines light by diffuse reflection within the chamber; and (c) anoptical aperture through which combined light is emitted from thechamber in a direction for lighting an area intended to be illuminatedby the system; the LEDs being coupled to supply the generated visiblelight to locations in the chamber and directed so that the visible lightsupplied from the LEDs is reflected one or more times off the reflectiveinterior surface of the chamber before emission in the combined lightthrough the optical aperture; and (d) a detector for detectingelectromagnetic energy of a wavelength at least substantially absentfrom a spectrum of the combined light from within the area intended tobe illuminated by the emission of the combined light through the opticalaperture; and a controller coupled to the LEDs for turning the LEDs onand off to turn the lighting system on and off, and when the LEDs areturned on, for controlling an amount of visible light 20 generated fromeach of the LEDs for inclusions in the combined light, wherein thecontroller is receives the detection signal from the detector.
 43. Thelighting system of claim 42, wherein the detector is coupled to thechamber so as to receive the electromagnetic energy of said wavelengthafter passage through the optical aperture into the interior of thechamber from the area intended to be illuminated.
 44. The lightingsystem of claim 43, wherein the detector is coupled to a location in thechamber at which at least a substantial portion of the electromagneticenergy of said wavelength entering the chamber from the area through theoptical aperture is diffusely reflected one or more times off thereflective interior surface of the chamber before reaching the locationof coupling of the detector.
 45. The lighting system of claim 42,wherein the detector is coupled to receive the electromagnetic energy ofsaid wavelength outside the chamber without passage through the opticalaperture into the interior of the chamber.
 46. The lighting system ofclaim 42, further comprising a source of electromagnetic energy of saidwavelength for emitting electromagnetic energy of said wavelength intoat least a portion of the area intended to be illuminated by theemission of the combined light through the optical aperture.
 47. Thelighting system of claim 46, wherein: the source of electromagneticenergy of said wavelength comprises an infrared (IR) emitter; and thedetector comprises an IR photodetector.
 48. The lighting system of claim46, wherein: the source of electromagnetic energy of said wavelengthcomprises an ultraviolet (UV) emitter; and the detector comprises an UVphotodetector.
 49. The lighting system of claim 46, wherein: the sourceis located for emission of electromagnetic energy of said wavelengthfrom outside the chamber into said portion of the region without passagethereof from the chamber through the optical aperture; and the detectoris coupled to a location in the chamber at which at least a substantialportion of electromagnetic energy of said wavelength entering thechamber through the optical aperture is reflected one or more times offthe reflective interior surface of the chamber before reaching thelocation of coupling of the detector.
 50. The lighting system of claim46, wherein: the source is coupled to supply electromagnetic energy ofsaid wavelength into the chamber in such a manner that substantially allenergy of said wavelength emitted from the source reflects diffusely atleast once within the interior of the chamber before emission throughthe optical aperture toward the region; and the detector is located fordetection of electromagnetic energy of said wavelength reflected fromwithin the region without passage of the reflected electromagneticenergy of said wavelength through the optical aperture.
 51. The lightingsystem of claim 42, further comprising a source of electromagneticenergy of another, different wavelength at least substantially absentfrom the spectrum of the combined light.
 52. The lighting system ofclaim 51, wherein the controller is configured to: modulate operation ofthe source to superpose data on the electromagnetic energy of said otherwavelength emitted from the source; and process the detection signalfrom the detector to capture any data carried by the detectedelectromagnetic energy of said wavelength.
 53. The lighting system ofclaim 42, wherein the controller is configured to implement thecontrolling of the amount of visible light supplied to the chamber bythe LEDs responsive to the detection signal from the detector.
 54. Thelighting system of claim 53, wherein the controller is configured toturn on and turn off the LEDs in response to predetermined changes inthe detection signal from the detector.
 55. The lighting system of claim42, wherein the controller is configured to process the detection signalfrom the detector to capture any data carried by the detectedelectromagnetic energy of said wavelength.
 56. The lighting system ofclaim 42, wherein the plurality of LEDs comprises a plurality of whitelight emitting LEDs.
 57. The lighting system of claim 56, wherein theplurality of white light emitting LEDs comprises: a first LED foremitting white light of a first color temperature; and a second LED foremitting white light of a second color temperature different from the 5first color temperature.
 58. The lighting system of claim 42, whereinthe plurality of LEDs comprises first second and third LEDs for emittinglight of different first, second and third colors, respectively.
 59. Thelighting system of claim 42, further comprising: another chamber havinga reflective interior surface, at least a portion of the interiorsurface having a diffuse reflectivity such that the chamber combineslight by diffuse reflection within the chamber; and an optical aperturethrough which the electromagnetic energy of said wavelengthsubstantially enters the other chamber from within the area intended tobe illuminated, wherein the detector is coupled to receiveelectromagnetic energy of said wavelength reflected within the otherchamber.
 60. The lighting system of claim 59, further comprising areflective mask constructively occluding the optical aperture of theother chamber with respect to the portion of the area intended to beilluminated.
 61. The lighting system of claim 42, wherein the fixturefurther comprises a reflective mask constructively occluding the opticalaperture of the chamber with respect to the area intended to beilluminated.
 62. The lighting system of claim 61, further comprising:another chamber having a reflective interior surface, at least a portionof the interior surface of the other chamber having a diffusereflectivity; and an optical aperture through which the electromagneticenergy of said wavelength 5 substantially enters the other chamber fromwithin the area intended to be illuminated, wherein the detector iscoupled to receive electromagnetic energy of said wavelength reflectedwithin the other chamber.
 63. The lighting system of claim 62, furthercomprising another reflective mask constructively occluding the opticalaperture of the other chamber with respect to the portion of the areaintended to be illuminated.
 64. The lighting system of claim 62, whereinthe other chamber is formed in the reflective mask.
 65. The lightingsystem of claim 64, further comprising another reflective maskconstructively occluding the optical aperture of the other chamber withrespect to the portion of the area intended to be illuminated.
 66. Thelighting system of claim 42, wherein diffuse reflection within thechamber produces a substantially uniform intensity distribution acrossthe entire optical aperture.
 67. The lighting system of claim 66,wherein the intensity distribution is sufficiently uniform that theentire optical aperture appears as a virtual source of light emissioninto said region.
 68. The lighting system of claim 66, wherein theintensity distribution across the entire optical aperture issubstantially Lambertian.
 69. The lighting system of claim 66, whereinthe intensity distribution across the entire optical aperture isunpixelated.
 70. The lighting system of claim 66, wherein the intensitydistribution across the entire optical aperture exhibits amaximum-to-minimum ratio of 2:1 or less.
 71. The lighting system ofclaim 66, wherein the chamber forms an optical integrating cavity. 72.The lighting system of claim 42, wherein: a first one of light emittingdiodes is for emitting visible light having a spectral characteristicand is initially active; a second one of the light emitting diodes isfor emitting visible light having said spectral characteristic and is aredundant element that may be activated by the controller on an asneeded basis.
 73. The lighting system of claim 42, further comprising asensor for detecting a characteristic of the combined light andproviding a feedback control signal to the controller.
 74. The lightingsystem of claim 42, wherein the chamber comprises: a dome having areflective surface; and a plate having a substantially flat reflectivesurface facing the reflective surface of the dome, coupled to the domeso as to form the chamber between the reflective surfaces of the domeand plate, at least a portion of one of the reflective surfaces of thedome and plate being diffusely reflective.
 75. A lighting system,comprising: an optical integrating chamber comprising a base, a maskseparated from the base, and a cavity formed in at least one of the baseand the mask, wherein: opposing surfaces of the base and mask arereflective, at least one of the opposing reflective surfaces exhibits adiffuse reflectivity, and the mask is sized and positioned relative tothe base so as to constructively occlude an active area of the base withrespect to a region to be illuminated by reflected light emerging fromthe chamber between the base and mask; at least one solid state lightemitting element for emitting visible light, each solid state lightemitting element being coupled to supply visible light to enter theoptical integrating chamber in such a manner that substantially alllight emitted from each solid state light emitting element reflectsdiffusely at least once within the interior of the optical integratingchamber before emission from the chamber toward the region; a detectorfor detecting electromagnetic energy from the region of a wavelength atleast substantially absent from a spectrum of the reflected light; and acontroller for controlling an amount of visible light supplied to thecavity by the at least one solid state light emitting element, whereinthe controller receives a detection signal from the detector.
 76. Thelighting system of claim 75, wherein: the cavity is formed in the base;and an aperture of the cavity forms the active area of the base.
 77. Thelighting system of claim 76, wherein the detector is coupled to theoptical integrating chamber to receive the electromagnetic energy fromthe region of said wavelength after reflection thereof within theoptical integrating chamber.
 78. The lighting system of claim 77,further comprising: a source for illuminating at least a portion of theregion with electromagnetic energy of said wavelength without reflectionthereof within the optical integrating chamber, wherein the detectordetects electromagnetic energy of said wavelength reflected from withinthe region.
 79. The lighting system of claim 78, further comprising:another optical integrating chamber having a reflective interiorsurface, at least a portion of the interior surface of the other opticalintegrating chamber having a diffuse reflectivity; wherein the source iscoupled to supply electromagnetic energy of said wavelength into theinterior surface of the other optical integrating chamber; and anoptical aperture through which electromagnetic energy of said wavelengthreflected within the other optical integrating chamber emerges toilluminate at least the portion of the region.
 80. The lighting systemof claim 79, wherein: the other optical integrating chamber comprises aportion of the mask serving as another base, another mask separated fromthe other base, and another cavity formed in at least one of the otherbase and mask, opposing surfaces of the other base and mask arereflective, at least one of the opposing reflective surfaces of theother base and mask exhibits a diffuse reflectivity, and the other maskis sized and positioned relative to the other base so as toconstructively occlude an active area of the other base with respect toat least the portion of the region to be 10 illuminated byelectromagnetic energy of said wavelength.
 81. The lighting system ofclaim 80, wherein: the other cavity is formed in the other base; and anaperture of the other cavity forms the active area of the other base.82. The lighting system of claim 75, further comprising: a source forsupplying electromagnetic energy of said wavelength for reflectionwithin the optical integrating chamber and illumination of the regionwith electromagnetic energy of said wavelength via the optical aperture,wherein the detector detects electromagnetic energy of said wavelengthreflected from within the region.
 83. The lighting system of claim 82,further comprising: another optical integrating chamber having areflective interior suiface, at least a portion of the interior surfaceof the other optical integrating chamber having a diffuse reflectivity;and an optical aperture of the other optical integrating chamber throughwhich electromagnetic energy of said wavelength reflected from theregion enters other optical integrating chamber, wherein the detector iscoupled to receive the reflected electromagnetic energy of saidwavelength from the region after diffuse reflection thereof within theother optical integrating 10 chamber.
 84. The lighting system of claim82, wherein: the other optical integrating chamber comprises a portionof the mask serving as another base, another mask separated from theother base, and another cavity formed in at least one of the other baseand mask, opposing surfaces of the other base and mask are reflective,at least one of the opposing reflective surfaces of the other base andmask exhibits a diffuse reflectivity, and the other mask is sized andpositioned relative to the other base so as to constructively occlude anactive area of the other base with respect to the region.
 85. Thelighting system of claim 83, wherein: the other cavity is formed in theother base; and an aperture of the other cavity forms the active area ofthe other base.
 86. The lighting system of claim 76, further comprising:a source for illuminating at least a portion of the region withelectromagnetic energy of another wavelength at least substantiallyabsent from the spectrum of the reflected light.